5 Seconds or otherwise, some "new guy" d*cking around in MP can Vanguard promote there way to more ending options than the most die hard RPG completionist.
This... isn't really the case. Each promotion requires a level 20 character, each level 20 character requires at least an hour or two to get. Each promotion nets you 75 points. It'll take you quite a few promoted characters, even at 100% effectiveness, to offset missing a bunch of quests.
I think it's the worse than SecurROM. What happens when EA shuts off the servers. I can't access my ME2 DLC on Xbox without being online to EA. How is this going to work in 5 years ? 10 years ?
This is a fairly serious concern of mine. I suspect one of two things will happen:
1. EA will take the path Valve has said they will take in the event of server outage, and release unlock patches for their content. In the event that they do shut down their servers, they're probably not expecting to sell a lot more copies of the DLC or game, so the gain in fan respect probably offsets the tiny loss of income from people pirating it a decade down the line.
2. The pirates will beat them to the punch and reverse engineer the authentication system to allow people to play through on their own.
If ME weren't as well-played a series, I'd be more worried, but given the attention I imagine one (or both) of those outcomes is fairly likely.
As for EMS... I find it to be a clunky abstraction put in place to solve two issues. The first is that some people probably complained that they didn't have a good way to figure out if they were ready for the suicide mission in the second game. I can understand that grievance, even if I disagree with how they chose to address it. The second is that it allows them to abstract away a lot more of the little side pieces they put in the game. Let's take a sidequest where you find a small prothean relic to help with translation efforts. There are a few ways they can handle the impact of that minor sidequest on the end game:
1. It can have no appreciable effect. Basically, the quest is only there to flesh out the world. This is okay some of the time - after all, not everything you find is useful - but if every sidequest is like this, only netting experience and maybe credits, you really have no reason to do them.
2. They can write in a specific triggered cutscene noting the impact of said sidequest. Remember Conrad's sidequest on the citadel? Basically like that. Since it's a sidequest of no real note, it can't be a game-changer - perhaps it allows them to translate some details on a defense mechanism that might remove a few enemies from a tough fight in the final run, or something - but nonetheless, said quest would have a concrete effect on the game in some way. The advantages of this is that it makes the player feel very invested in the world, and that there are consequences to your actions. The downsides of this are that it takes a TON of developer time, and if every little thing you do has an obvious effect in the end game it can make the world feel much smaller.
3. You can have each sidequest feed into an aggregate score, which has several breakpoints. This is basically what they did: Your sidequests matter, but you can pick and choose how you want to go about setting them up. The advantage is in player flexibility - they will never feel obligated to do something - but the downside is that it feels artificial. Why should getting four hundred pieces of prothean wreckage be the same as building a giant army? It doesn't make a whole lot of sense under close examination.
Were it up to me, I would have taken a hybrid approach: Rather than a single aggregate EMS, there would be a "crucible progress," "army strength," "morale," and possibly other categories of readiness. You'd then have a lot of either/or missions: You could do an operation to rescue an army, increasing your military might, but at the cost of not retrieving some piece of important research data. The endgame would then play out differently depending on whether you went for a large conventional force (saved a lot of people, but threw them into a meat grinder to win) versus a more ruthless solution (left people to die or be taken in order to complete and perfect a superweapon). Either way, people are going to end up dead, the reapers would end up dead, but how you went about it would say a lot about who you were.
Ah, well. What could have been...