78 réponses à ce sujet

[Valmar]

1) The Catalyst needs to be dormant so it will not be detected by the Citadel races.  They need to believe the Citadel is a "gift" from a previous species that abandonned it for the plan to work (Babylon 5: Babylon Squared, but with a twist ).  It relies on the Keepers to wake it at the proper time, that system as worked before, it would be illogical to change it.  Usually, by the time a race discovers the true purpose of the keepers, it's too late for them.

 

2) The Catalyst was created by the Leviathans who may not have wanted to give it that much control over the Citadel, and it is most likely incapable of going beyond its original programming by itself, otherwise it would have done so and found a better way to deal with the synthetic problem, by taking charge over the entire galaxy and preventing the rise of machines in the first place.

 

1. I get the need to remain undetected, I just fail to see why the catalyst would have to remain dormant to do so. It is the programming that runs the citadel and clearly the council has very little understanding of that programming as it stands. The protheans were able to hide a functional mass relay right in the open. It clearly wasn't completely dead since the lore tells us it emitted hums or what have you. Theoricially someone should had been able to figure out "hey, this is a REAL relay, not just some piece of artwork, it has actual functioning wiring networks and everything!"

 

Yet they never do. The council races seem to be very incompetent when it comes to discovering the inner workings of the Citadel. There are places aboard the station they've never even ventured or have no idea exist. The reapers build reapers there for crying out loud. I don't see why the catalyst would have to be completely dormant the entire time just to keep people from seeing him. EDI managed to stay 'secretive' aboard the Normandy despite having daily interaction with them.

 

As long as the catalyst draws no attention to itself directly there's no reason it cannot remain awake to monitor all the stuff going through its servers. But okay, for sake of argument lets say it does go into sleep mode. Why doesn't it wake up at the 50k mark and turn on the relays? It would only take a second. Even if for some strange reason the citadel races instantly know its there it would be too late for them to do anything. It would just call in the reapers.

 

The keepers interact with the citadel physically. The catalyst IS the citadel. It doesn't need to wobble up to some monitor or dashboard to activate some dials and knobs to activate the citadel relay. The keepers are watched by CSec security cameras, as we see aboard the Shadow Broker's ship. You can observe the keepers in the act of starting up a relay, yet of course its never stopped them because the citadel races know nothing and do nothing to stop it. So then why would they notice the catalyst, the Citadel OS, activating the relays?

 

It'd be both quicker and more discreet than the keepers.

 

2. Yes, the Leviathan's built the Catalyst. The catalyst built the Citadel though, not the leviathans. The Leviathan's had no say in how much control the catalyst has of the citadel, the citadel was not made by the leviathans. The citadel is a reaper construct, a catalyst construct. The leviathans are completely irrelevant to this. The catalyst existed before the citadel was constructed. It is a construct of its own creation that it integrated itself into.

[Catastrophy]

Because they need it for later. Their "plan" which I don't care about. Blow up all the stuff! Relays and Citadels are a crutch and shackles for civs. True champions will figure out ways to navigate the galaxy without.

[Kabooooom]

Hey, cool subsection, never saw it before. Is it new?

On topic: My explanation goes like this:

Usually the reapers would use the keepers to open the citadel relay and jump in. At this point, they take everyone by surprise and immediately take over the citadel. All is good for the reapers.

However, this time, they had to come into the galaxy from the outside. They still tried to get directly and surprisingly to the citadel through the alpha relay but that plan was messed up by Shep in Arrival.

So now, they would have to go there the normal route, at which point the citadel would have some advanced warning of an attack and could close the Citadel arms. Even when Sovereign conducted a surprise attack in ME1, he barely made t inside, the reapers in ME3 must figure that none of them coul make it in there in time.

Since - once closed - the citadel is impenetrable (quantum shielded) the reapers are screwed. Even they can't overcome this obstacle. Also, Citadel or no, they do have overwhelming force one way or another, so they do go for the home-worlds of the Citadel races instead. At the same time, they rather try to get someone on the inside. First attempt is the Cerberus coup (although it is unclear if this was actually initiated by the reapers themselves, I doubt it or it would have made sense for them to attack at that point, so it was likely TIM's/Udina's own initiative). That fails as well. Second attempt is to get TIM there while the alliance is busy attacking Cerberus HQ. This time it works and they do take over.

This is he only way, it makes sense to me that the reapers are not going after the Citadel. Basically, they are afraid that the organics will close it and fortify it, which would cause them more problems than just ignoring it for the time being. Of course, all this is sort of dependent on the fat that star kid for whatever reason doesn't have control over the Citadel, except for his little elevator to heaven (but let's not go to the ending for now).

This is almost exactly my interpretation of the situation as well, and it is supported by in-game lore evidence and makes logistic sense.

I only add a couple things:

1) travel across the relay network is not instantaneous as it is portrayed in game. Relay travel is, but you have to travel through space between relays in a given system, which takes time. It takes approximately 15 hours to reach the Citadel from Eden Prime, for example. That's another reason why Sovereign had to launch as much of a surprise attack as possible.

If the organics posted sentry fleets or sentry drones near all bottleneck primary relays leading to the Serpent Nebula, they would likely have HOURS of advanced notice of a Reaper attack and close the arms. A subversive attack is therefore far smarter.

2) Javik gives you an oft overlooked and ominous clue - he tells you that the Reapers allow refugees to gather at camps, and deliberately sneak in indoctrinated refugees to bring them down from the inside. The taking of the Citadel happens off screen, but it was very likely more than just TIM that helped them take the Citadel from the inside.

[Redbelle]

That last point taps into something mentioned in the beginning of the thread. Saren and Sovereign contradicting each other in terms of needing organics.

 

Saren's statement of the Reaper's needing organics always seemed to me to be a belief born of hope inthe face of hopelessness. Not so much that he's actively contradicting Sov. More that it's the only branch he has to cling too.....

 

Sov on the other hand seems dismissive of organics but uses them like tools to achieve an effect. And if a tool breaks, what the hey.... they have replacment's.

 

It seems to me that neither Saren or Sovereign contradict each other. Each simply has views they keep from each other. Neither sharing. But ultimately living in a master/slave relationship where the master allows the slave to think what he likes until the time comes to remind them who wields the power.

 

The Reapers have the luxery of being the ones with the biggest stick. They can dictate terms or destroy resistance and then demand terms from the survivors. But likeall warfare, positioning and working to a time table to acheive maximum effect when they strike a position is key. Reapers always seem to attack in overwhelming force. To achieve this Reapers need to co-ordinate to position their forces, which takes time. Time works against invader's in that it allows defenses to be arrayed which in turn means the Reapers must commit more forces to the assualt to overcome the defense.

 

The point is the Reapers haven't the luxery of time in Shepards cycle. The relays are still up so the free races can reposition their forces to meet the threat. But the Reaper vessles outclass free race vessels by a wide factor.

 

The Reapers counter this by amassing more vessels than would otherwise be assigned if the relay network was down. Meaning fewer planet's can be harvested at any one time.

 

Keep in mind the purpose of the cycle is the harvest. And the Reapers want it done ASAP so they can get on with preparing for the next cycle. Overcoming obstacles in as expedient manner as possible to continue progressing towards their clean slate galaxy model that would allow other races to reach the Reaper defined pinnacle of civilisation. In the Reaper model where the Reaper is the master, they aren't acting in the role of invaders, though that is essentially what they doing. The Reapers consider themselves more as overseers quelling a rebellion. Using those they made slaves, allowing them thin sliver's of hope, to use that to work against their own side.

[Iakus]

Most people are wrong when they say ME3 was good for 99% then the ending sucked. The writing started sucking back in ME2 but lets not go that far.

 

The whole point of the first game was to stop Sovereign from reaching the Citadel and opening it as a relay to dark space where all the other reapers where here they explain that they could shut down all the relays and cripple the organics war effort. Well why didn't star child just do it? Another plot hole the size of Lisa Ann's birth canal.

 

But back to ME3. If the reapers just attack the Citadel first they could have shut down all the relays cutting off any way for anyone to move around the galaxy and thus winning the war. IT MAKES NO SENSE. I would like to sit down with Mr. Walters and ask these questions because I have lots.

See now it made a little bit more sense if they stuck to Drew Karpyshyn original plot of the reapers needing to find a way to stop the spread of dark energy by going to earth and making a human reaper because they were running out of time, and they believe humans were the way to stop it.

Still sucks the big one but it made sense why they would needed to go to earth before doing anything.

 

I believe I've given this answer before in other threads.  But long story short, the reason the Reapers didn't hit the Citadel first:

 

ME3 would have been a frakking short game if they did.

[Cheviot]

Well why didn't star child just do it?

 

Because the Catalyst was "paralysed", or at least stuck in a sleep similar to the one the Reapers settle into in dark space between Cycles.  The Prothean work to disable the signal controlling the Keepers meant that the Catalyst couldn't be "woken" as normal, which is why Soverign had to make a direct assault.  As to why the Reapers didn't attack the Citadel directly, there are two reasons:

 

1) They couldn't emerge from the Relay in the Citadel, so they would have to go through the other systems anyway.  Besides, it wouldn't have changed much; without Shepard's victory, the Reapers would've won within 2 years anyway, so it was no more than a minor hiccup in the normal run of things.

2) An important part of their plan involving the Citadel had changed.  Instead of the Catalyst-Citadel liquidating the population of the Citadel in order to run, the Citadel was brought to Earth so its population could be used too, since the plan to use humans as the basis of a new Reaper in ME2 failed.

[Ithurael]

You do realize that the prothean sabotage - as stated by the lore - ONLY affected the keepers right? The sabotage was meant to block the keepers from receiving a signal from soveriegn. This signal - once sent to them - made them trigger the Citadel relay.

 

Then, there is the issue of starjars power over the citadel during ME1. As he is the collective consiousness of all reapers he would know what soveriegn knows and how the signal wouldn't work. And he didn't have any new solutions provided by the crucible. So yeah...ME1-3 are moot

 

Details here:

http://forum.bioware...ity/?p=18388908

[Redbelle]

Because the Catalyst was "paralysed", or at least stuck in a sleep similar to the one the Reapers settle into in dark space between Cycles.  The Prothean work to disable the signal controlling the Keepers meant that the Catalyst couldn't be "woken" as normal, which is why Soverign had to make a direct assault.  As to why the Reapers didn't attack the Citadel directly, there are two reasons:

 

1) They couldn't emerge from the Relay in the Citadel, so they would have to go through the other systems anyway.  Besides, it wouldn't have changed much; without Shepard's victory, the Reapers would've won within 2 years anyway, so it was no more than a minor hiccup in the normal run of things.

2) An important part of their plan involving the Citadel had changed.  Instead of the Catalyst-Citadel liquidating the population of the Citadel in order to run, the Citadel was brought to Earth so it's population could be used too, since the plan to use humans as the basis of a new Reaper in ME2 failed.

I take a different approach to the Catalyst..... It was never envisioned to be a part of the Mass Effect story..

 

Given everything I've seen I believe the Catalyst was developed, not primarily as an in game solution to bookend the installment of ME3, but rather as a means to end the game on some kind of easily recognizable end game trope in order to avoid additional development time being put the sequence of events at the end in order to meet time or budget or release deadlines. One or more. At this point I've given up trying to unearth which.

 

The reason I think this is that while there have been instances where gamers can point to events and say that narrative fails, there has never been an event in ME gaming that had so many decrying the fall in quality in terms of presentation and content of a scene. While the Cat's choice of words and philosophy, combined with what it is, may speak to things of a higher nature than simple survival of a species, it's placement, and lack of character in what is a character led game was out of place by a wide margin.

 

If we accept that the Catalyst was ill considered as an end game utility, then the question becomes why..... in a game in which many writers who gave these character's their words, would suddenly throw the Cat at us, without taking into account the player relationship and the player circumstance of where they had taken their Shepard's at that point. The only conclusion I for one can draw is that, for whatever reason, the Catalyst wasn't subject to the quality control testing that the rest of the game was subject to and thus, never envisioned as the end game gatekeeper.

 

In other words, to generalize. I don't see the problems with the Catalyst being an intra game issue where it's motivations and actions demand more scrutiny in a game that had no problem getting players to understand alien races cultures, beliefs, tolerances, histories etc..... The Cat's problem lies in the extra game environment when it was conceived and then badly thought out without anyone stopping the process to question how the Cat could fit in the game. Let alone explain it's presence in a flowing narrative primarily told from the players perspective.

[Cheviot]

You do realize that the prothean sabotage - as stated by the lore - ONLY affected the keepers right? The sabotage was meant to block the keepers from receiving a signal from soveriegn. This signal - once sent to them - made them trigger the Citadel relay.

Yep, and the Keepers are needed for the Catalyst to "wake up"; they maintain the body - their strange, quick, seemingly random building work on the Citadel starts to make sense if you see it like a body repairing itself after trauma - and to process the victims needed to sustain the Catalyst (as they are doing when Shepard appears on the Citadel after reaching the Conduit).

[Ithurael]

Yep, and the Keepers are needed for the Catalyst to "wake up";

 

Citation? Lore? Dialog? Scene?

 

Where does it say that starjar needs the keepers to "wake up". He was perfectly awake when shep showed up. Soveriegn was awake during ME3 and starjar is the collective consciousness of the reapers - including Soveriegn.

 

 

 

they maintain the body - their strange, quick, seemingly random building work on the Citadel starts to make sense if you see it like a body repairing itself after trauma

Maintenance =/= ownership nor does maintenance==control. they are slaves and they respond to (as cited by the dialog and the lore) the citadel. So, how can they respond to something they have to wake up? That makes no sense. In any system, there is an operator and a function. The operator calls the function to do what it is designed to do. This hierarchy is established via the Vigil convo and the codex. The Keepers respond to the citadel.

 

And the citadel is the catalyst and is part of the catalyst

 

Source:

"The keepers are controlled by the citadel"

 

"They evolved so that they only respond to the signals emitted by the citadel itself"

 

Then there is the issue of what is closing those arms in the control cinematic. We are never told what. We have to go off what we know. And we know:

The keepers activate citadel functions

The keepers respond to the citadel

The Citadel is part of the reaper master consciousness and its home.

 

 and to process the victims needed to sustain the Catalyst (as they are doing when Shepard appears on the Citadel after reaching the Conduit).

 

What? The victims don't sustain the catalyst. It isn't some blood drinking vampire. The theory shep and anderson had was that they were making a new reaper in the citadel (albeit completely different from how the collectors did it). Making a new reaper does not sustain the catalyst. He did not and does not need them to exist. He existed before them and then created & controls them. They may give him purpose but in the end he could scrap them all and start again with another kind of robot monster.

 

I smell headcanon here.

[themikefest]

This is why the reapers didn't go to the Citadel at the beginning

 

Spoiler

[Redbelle]

Likewise the Master Control Unit being related to the Catalyst is also head canon. There's evidence to support the claim but it's never implicitly stated that one and the other are related except by tenuous association by taking ones meaning and searching for connection to explain how things in the Citadel connect.

 

The Master Control Unit is believed by some to be a location, being the tower. Others believe it is a regulating system that supports the Citadel. Maybe it's both. Maybe it's more. It cannot be proven or dis-proven. to some the MCU is the panel Shepard used to open the arms.

 

Then there's the question of, are their other factors involved in opening and closing the arms? Say, run program "control". Close arms on finalization of process. Yet another outcome that is plausible given the technology, but cannot for certain say it is what happened?

 

I think the thought put into the ending by the fans, had it been reflected in the games cinematic and conversations would have made things clearer for all. But as the ending stands, I think the only thing we can rationally agree on is that these rationalizations for what happened are plausible... but not certain.

[Cheviot]

Citation? Lore? Dialog? Scene?

 

Where does it say that starjar needs the keepers to "wake up". He was perfectly awake when shep showed up.

Evidence that the Catalyst was "asleep":

-Reapers need to hibernate between Cycles to conserve energy;
-While in hibernation, Reapers are vulnerable;
-The Catalyst is essentially a proto-Reaper, based on the same technology (in fact, the basis for that technology), and so will share the same limitations where technology is concerned;
-The Protheans from Ilos sneaked onto the Citadel after that cycle's Harvest, when the Reapers had left for dark space and the Catalyst had went into hibernation.  It was at this point they altered the keeper signal.

 

Therefore, the Catalyst was "asleep", unable to be awakened because the keepers could not be communicated with.
 

 

Evidence that the keepers are needed to "awaken" the Catalyst.

-The keepers maintain the Citadel;
-In the cutscene at the start of "Citadel: The Return", the keepers are processing multiple dead bodies in a way that reminds Shepard and Anderson of the processing of victims by the Collectors.  Since none of the Citadel races would want this to happen - and, more importantly, lack the capability to control the keepers - this is a sign that the keepers are back under Reaper control;
-When the keepers are back under Reaper control, the Catalyst appears.
-The Catalyst is an intelligence housed and supported by the Citadel, an intelligence that can control the Citadel when the keepers are back under Reaper control.  In essense, the Catalyst and the Citadel are one and the same, mind and body.  

 

So yes, by the time Shep meets him, the Catalyst is awake, but that is due to the work of the keepers.

 

 

So, how can they respond to something they have to wake up?

 

We don't consciously order our cells to heal a broken bone, yet it heals all the same. In the same way, the Keepers heal the Citadel after the battle at the end of ME1. 

 

 

Making a new reaper does not sustain the catalyst

That's true, but there isn't a new Reaper. Shepard and Anderson's suspicions are close but not exactly right.  The Collectors processed the people they kidnapped in order to sustain the Human-Reaper in ME2, and the same process is happening here, but it is to sustain the Catalyst itself.  In the same way the harvested remains of previous Cycles are used to give life to a new Reaper, the harvest of Earth is used to return function to the Catalyst.  This is what I mean by "waking up".

[themikefest]

There is nothing to prove what the reaper do in dark space. Its speculation by Vigil. For all I know they sit back  and drink booze while playing cards for 50 000 years

 

I do believe once the Crucible attached to the Citadel, the catalyst is awakened letting it activate the elevator that brings Shepard to the decision chamber

[Ithurael]

I will now list out your headcanon (bolded)

 

Evidence that the Catalyst was "asleep":

-Reapers need to hibernate between Cycles to conserve energy;
-While in hibernation, Reapers are vulnerable;
-The Catalyst is essentially a proto-Reaper, based on the same technology (in fact, the basis for that technology), and so will share the same limitations where technology is concerned;
-The Protheans from Ilos sneaked onto the Citadel after that cycle's Harvest, when the Reapers had left for dark space and the Catalyst had went into hibernation.  It was at this point they altered the keeper signal.

 

Therefore, the Catalyst was "asleep", unable to be awakened because the keepers could not be communicated with.
 

 

 

Thankfully it isn't as much headcanon as most.

 

However you are right on a few points

- the reapers hibernate = we are told this

- in hibernation they are vulnerable = we are told this

- The protheans did sneak onto the citadel and altered the keepers to not receive the signal from sovereign = we are told this

 

However, you are assuming that the catalyst has the same limitations. That is never said anywhere. Nor is it inferred. And nowhere is that shown. The keepers are still maintaining the citadel when the Asari found it.

 

What we know:

The keepers respond to the citadels signals

The Citadel is part of Starjar

 

What we can infer:

Starjar (the citadel) is sending the signals to the keepers

 

And I am not affirming the consequent here. This is the observable lore. This is literally what we are seeing

 

 

Evidence that the keepers are needed to "awaken" the Catalyst.

-The keepers maintain the Citadel;
-In the cutscene at the start of "Citadel: The Return", the keepers are processing multiple dead bodies in a way that reminds Shepard and Anderson of the processing of victims by the Collectors.  Since none of the Citadel races would want this to happen - and, more importantly, lack the capability to control the keepers - this is a sign that the keepers are back under Reaper control;
-When the keepers are back under Reaper control, the Catalyst appears.
-The Catalyst is an intelligence housed and supported by the Citadel, an intelligence that can control the Citadel when the keepers are back under Reaper control.  In essense, the Catalyst and the Citadel are one and the same, mind and body.  

 

- The keepers maintain the citadel AND respond to signals from the citadel.

- The keepers were never under reaper control post sabotage. They respond to the signals from the citadel. And the citadel just happens to be the reaper master consciousness

- Again, the keepers were never set back under reaper control. What we are told is that post sabotage they respond to the citadel and the citadel alone. You are assuming they are under reaper control without any proof.

- The bolded is never stated - anywhere - nor is it shown via cutscenes or gameplay or codex or anything.

 

Again before the sabotage (what we know) the story tells us the keepers respond to:

- Signals from the Citadel

- Signal from Soveriegn

 

Post sabotage (what we know) the story tells us the keepers respond to:

- Signals from the Citadel only

 

And it just happens that the citadel is the reaper master consciousness home and part of the reaper master consiousness

 

 

 

We don't consciously order our cells to heal a broken bone, yet it heals all the same. In the same way, the Keepers heal the Citadel after the battle at the end of ME1. 

 

AI =/= Organic. Please try again.

 

Also, this is further negated by the blue ending:

 

hmm...I wonder what is closing those arms...

 

 

 

That's true, but there isn't a new Reaper. Shepard and Anderson's suspicions are close but not exactly right.  The Collectors processed the people they kidnapped in order to sustain the Human-Reaper in ME2, and the same process is happening here, but it is to sustain the Catalyst itself.  In the same way the harvested remains of previous Cycles are used to give life to a new Reaper, the harvest of Earth is used to return function to the Catalyst.  This is what I mean by "waking up".

 

All the bolded is headcanon. What the bodies were supposed to be used for is rendered moot by the events that happened. Shep theorizes that they are making a reaper, or are in an early stage of doing so. The processed people are then used to make a reaper. There is no evidence to support that organic bodies would or could sustain starjar.

 

Please, I beseech you, don't assume, find the information in the lore first. Then respond

[StarcloudSWG]

Vigil *speculates* that the Reapers hibernate in dark space. Vigil does not *know*. For everything other than what Vigil has recordings of and/or has observed, Vigil is an unreliable narrator.

 

Fact: Reapers took the Citadel in the opening moments of the Prothean Extinction.

Fact: Reapers arrived via the mass relay built into the Citadel. A function the Protheans were unaware existed.

Fact: Reapers committed genocide on the Prothean Empire. It took hundreds of years.

 

Fact: Protheans figured out the Keepers were essential to triggering the mass relay function of the Citadel.

Fact: Protheans figured out how to disable/interfere with the trigger function embedded in the Keepers.

 

Strong inference: Protheans successfully made it to the Citadel and sabotaged the trigger function.

Strong inference: Protheans died on the Citadel.

 

Fact: Protheans also figured out how to briefly override Citadel functions with a program hack that they archived with Vigil.

 

Just about everything else Vigil says regarding the Reapers, particularly where they go between mass genocides, is speculation on its part.

[Gago]

Well if I have to think of an excuse I would say that maybe they don't take the Citadel right away because in the current cycle the races are more decentralized than for example the Prothean and their Empire which was very centralized. In the current cycle the races aren't dependent on each other as much as the ones in the previous cycle and thus they (current races) wouldn't be that handicapped and could adapt from the Citadel loss. But still, this is a far stretching scenario but hey it is just a theory.

[TMA LIVE]

I think they didn't attack the Citadel first because if they did, the doors would be locked, preventing them from getting inside until they build the conduit on Earth. And if they tried forcing their way in, the Citadel would be destroyed in the process, killing their creator and there new collector base. In ME1, they were dependent on Saren attacking from the inside, to allow Sov the chase to get inside the Citadel before the doors closed it out. In ME3, the closest they have to a Saren is TIM.

[Iakus]

I think they didn't attack the Citadel first because if they did, the doors would be locked, preventing them from getting inside until they build the conduit on Earth. And if they tried forcing their way in, the Citadel would be destroyed in the process, killing their creator and there new collector base. In ME1, they were dependent on Saren attacking from the inside, to allow Sov the chase to get inside the Citadel before the doors closed it out. In ME3, the closest they have to a Saren is TIM.

 

the Reapers have used indoctrinated refugees to capture worlds before.  Why not the Citadel?

 

Heck Cerberus very nearly succeeded in doing something very similar.

[Esthlos]

Well if I have to think of an excuse I would say that maybe they don't take the Citadel right away because in the current cycle the races are more decentralized than for example the Prothean and their Empire which was very centralized. In the current cycle the races aren't dependent on each other as much as the ones in the previous cycle and thus they (current races) wouldn't be that handicapped and could adapt from the Citadel loss.

I agree with this.
This cycle doesn't use the Citadel to host their government: they made it a melting pot, and housed embassies and representatives there, and not even every race does.
And since there is competition if not straight up conflict between the races, it is likely that the census data stored in the citadel isn't very accurate, and not by error.

As we know from the asari strategist in ME3 predicting Reaper movements from a piece of reaper code, the Reapers are predictable.

Now, what do we know about their harvest strategy? That they start the harvest with a surprise attack at the governing heart of the cycle.

What do they do in ME3? They start the harvest with a surprise attack at the governing heart(s) of the cycle, the homeworlds.

Why don't they take the Citadel until the end?
Well, let's see: as far as we know, they usually take the Citadel first in order to
-obliterate the cycle's government first
-get census data
-shut down the mass relay network

In this cycle
-the cycle's governments are not on the Citadel
-the census data on the Citadel isn't accurate enough to actually be useful (the Collectors dealt with the cycle's races, so they must have known that the galaxy wasn't united enough to trust such sensitive data in a shared archive)
-they attacked multiple systems at once instead of picking them off one at a time, and so they might have found it more useful to leave the network open, and don't consider the cycle using it too enough of a problem to have shutting it down a priority.

It makes sense to me that they didn't go after the Citadel first in this cycle...

As for Saren needing the Conduit: I think that he did try to access the controls manually before Eden Prime, but was denied access because the Protheans locked it.
As far as I know, at first he was simply looking for the key to unlocking the controls, and looking for the Conduit more as a backup plan in case by the time he found that key he didn't have access to the Council tower anymore.
He must have guessed that finding one would lead to the other, because it must have been the same group of surviving Protheans to use both, so after being exposed he just kept looking for the one he found hints to.

[KrrKs]

Leaving the Relay net open and allowing the opponent to bring in massive reinforcements (especially to places like Palaven, where the reapers are struggling/advancing very slowly anyway) does not seem like a smart move imo.

[themikefest]

Had the Protheans scientists not disrupted the signal, the reapers would come through the Citadel wiping out this cycle fairly easily. Because of what the Protheans did, it gave us a chance to defeat the reapers. 

[Reaper-Synthetic]

They were too arrogant for their own good. Had they attacked and seized the Citadel right at the start of their invasion and locked down the Relays, their chances of success would have been virtually 100%. But they were too arrogant of their own success and didn't see the need to seize the Citadel and lock down the Relays and that cost the Reapers their ''lives''.

 

Although I am not quite sure if all Reapers were killed by Crucible. Was I Harbinger I'd leave some Reapers behind me to the dark space in case things go FUBAR and have them act as a backup coming to reap the galaxy once the FUBAR event happened.

[Esthlos]

Leaving the Relay net open and allowing the opponent to bring in massive reinforcements (especially to places like Palaven, where the reapers are struggling/advancing very slowly anyway) does not seem like a smart move imo.

Spoiler

Isn't this exactly what happens on Earth in the end? Yet, as far as I know, if it weren't for the Crucible even that massive counter-attack against just that portion of the Reapers' fleet would have at most caused the loss of a few Reapers...

Although I am not quite sure if all Reapers were killed by Crucible. Was I Harbinger I'd leave some Reapers behind me to the dark space in case things go FUBAR and have them act as a backup coming to reap the galaxy once the FUBAR event happened.

Maybe the Reapers are too arrogant to consider their own destruction a real possibility worth preparing for?

[Reaper-Synthetic]

Maybe the Reapers are too arrogant to consider their own destruction a real possibility worth preparing for?

Well that might be the case. From their POV they've been annihilating organics for billions of years with no problems. Even the advanced protheans fell mercilessly. So why would they be afraid of this cycle at all.