a.) And about all your choices, they do matter. It's not because you don't see every single one of them that they don't matter.
b.)) I guess some Reapers are just more arrogant than others. Each Reaper has a different personality (we've seen it from Sovereign, Harbinger and that Destroyer on Rannoch).
c.) And the Catalyst appears as the kid from Earth because it manifested itself as something Shepard would understand. Why it chose this form? I don't know, maybe because seeing that kid die impacted Shep. And why would he not trust it? What other choices does he have? He's at the Crucible, the thing they've been building to defeat the Reapers, the 3 options are there and the Catalyst only explains them.
d.) - TIM wanted to use the Reapers for humanity only. He wanted to make Humans superior by using the Reapers. Shep might change his idea of Control because now it's fully explained and he undestand eveything he could achieve for the galaxy.
e.) You're talking like the Reapers are evil and that choosing Synthesis makes them win. Yes, in way, it makes them ''win'' but they're not evil. Synthesis stops the conflict between Organics and Synthetics, which is why the Reapers exist. The Reapers are not evil, they're only doing what they were programmed to do. (And yeah, walking around with Reaperized people is extra creepy.)
f.) Loosing the Geth and EDI if you chose Destroy is part of the story. It's a sacrifice. It's part of the choice, accept it. I'm gonna say it again, you're not making the game, you don't decide everything.
a.) nobody expects that eating a cheeseburger or a hamsandwich matters in the end, but making peace between the Geth and the Qarians should matter, but the Genocide that Bioware commits against the Geth in the Destroy ending basically made your success in ending a 300+ year long war OBSOLETE. That's what pissed people off.
b.) Each reaper has a different personality? That totally contradicts that Starkid is running the whole show and the reapers are HIS TOOLS. Also, synthetics are supposed to operate with linked AI, not as individuals. Yes, I know the bullshit story from Walters that they're harvesting civilizations to "keep their essence", whatever the hell that is supposed to mean. I doubt Leonardo Da Vinci can recognise his Mona Lisa in the human reaper... Total bull...
c.) I can tell you why the Starkid is there - because Walters with his b-grade writing skills thought ripping the creepy kid from the Silent Hill videogames would be a great idea. Also stop pretending he gives you choices. A choice is by definition something I decide for myself, not standing before the headsman and chose death by axe, sword, or just getting your arms chopped off. The catalyst also does not "explain" them. He (aka Mac Walters) simply LIES to you when he says "synthetics will always kill organics". It's a fantasy from bad sci-fi writers.
d.) nope, control would never work. Shepard gets killed and a copy of his "brain" gets uploaded into a computer. That's not Shepard anymore at all. It has no soul and could simply go crazy over time. Also, Imagine the Shepard-AI would get destroyed (asteroid striking the Citatel, sabotage, etc...) the reapers would be set lose again...
e.) the reapers ARE evil. Please, don't tell us that a Holocaust on Galactic level can be justified by any dumb ass theory from a retarded AI. Even if it would be true that synths always kill all organics - if the AI and the reapers weren't evil they could easily come up with a better method of "harvesting" all the people that doesn't include a 100+ year long brutal and disgusting war, terrifying organics, turning them into abominations, etc... So there's no way in hell you can say they're not evil. You have heard about euthanasia - basically letting old people die in peace instead of prolonging their suffering when they are terminally ill, now what the reapers are doing is - instead of euthanasia, where you just unplug their life-support machines, or give them meds, so they can peacefully fall asleep and die, you impale grandpa on spikes, lock him into a container to liquify his guts, etc, all at full conscious level and with the knowledge he'll die a horrible painful torturous death.
Not EVIL at all, right?
f.) loosing the Geth is not a sacrifice, it is bad writing, just as when J.R.R Tolkies would have ended the Lord of the Rings by telling Frodo: "hey, you can defeat Sauron, but this will kill all the Dwarves in Middle-Earth." The ending just makes no sense and is crappy literature.