I take the Renegade interrupt and shoot the Bioware writers, and the producers who allowed these endings to ship.
The short, spoiler-free version summary that someone expressed on a forum:
"Okay, guys, how do we wrap up 5 years worth of an amazing video game series and 90 hours of gameplay?"
MAGIC.
"But.. it's SF... in the future, with space ships and shit..."
SPACE MAGIC.
"Uhh. What about alternatives, choices, morality?"
COLOR-CODED SPACE MAGIC.
"BRILLIANT!"
Thoughts about the ME3 endings:
Fuck the Deus ex Machina/Lion-Turtle, fuck it right to hell. There are a million less narratively insulting ways to exposit the allowable decisions than 'inexplicably have The Creator around on the Citadel all along, and have him decide that you're cool enough to push a button'.
The whole damn thing is just so lazy, lazy, lazy, lazy. There's a limit to how much 'open to interpretation' you can write before you're just being lazy. Photoshopped stock footage doesn't exactly inspire confidence in the amount of effort put into this, either.
There are big fuckoff loopholes like 'where the fuck is the Normandy going' and 'why is everyone who was in London suddenly on it'. If it fled before the Crucible fired, why? If it didn't, since when is there a tree-world in Sol? It's just bad writing, and a producer should be fired for not paying attention to basic continuity. But anyway, onto the three endings.
Synthesis Ending:
The 'best' option makes no fucking sense, none at all. First of all it's SPACE MAGIC of the worst kind, makes no scientific sense ('trees with wires, this is synthesis, huzzah') in a series that prides itself on Sir Isaac Newton being the deadliest motherfucker in space, a series that explores the challenges of feeding species based around different kinds of proteins. (I'm not asking for hardcore realism in science fiction, but this is jarringly tacky.) And the least they could have done is animate Joker differently to show how synthesis heals his condition, demonstrating that it can help us be more than we could be otherwise (a point already made in the Quarian/Geth alliance, with the Geth helping Quarian suits heal Quarian immune systems, but it doesn't hurt to emphasize how very 'best' this ending is).
But it doesn't actually solve Deus' Dilemna, either, if we accept his paradigm (which we shouldn't be forced to, see below). How does adding wiring to all the organics, and a little flesh to all the synthetics, prevent them from building more synthetics who'll rise up and wipe everyone out (if that is, indeed, inevitable)? Plus it's totally uncool to just declare, to make the choice for everyone in the galaxy, that we're all going to be synthesized into organosynthetics because it's the only way to have peace. Isn't that what harvesting did anyway? Sure, this is much less horrific than that, but still.
Most importantly, the 'best' option suffers from not actually invoking Take A Third (well, Fourth) Option, which is what the moment is crying out for. Deus shows up and explains his paradigm of inevitability of synthetics being created, rebelling, and wiping out organics completely, which (at least, in a straight paragon run) you have demonstrated to be untrue; you should be allowed to challenge his framing. Why, in a game that immerses the player in conversation options, is Shepard silent about the Geth and Quarian alliance (or even simply the Geth choice to isolate rather than search and destroy)? What about EDI (yes, fuck EDI, but still), which the game spends a huge amount of narrative time humanizing in order to demonstrate, definitively, that humans and AIs can learn to live in harmony? If the exact same stupid space magic synthesis had been presented as Shepard's defiant idea, framed by examples of events formed by her decisions in the games, that, at least, would have provided some FUCK YES catharsis and closure.
The other two options, at least, I can salvage via interpretation, but because there's so little explained/explored about the implications, I refuse to give the writers any credit. I'm having to reach too far on my own.
Control the Reapers Ending:
I vaguely like the switch-up of good and bad at the end, if you argue that by sacrificing yourself and controlling the Reapers (thus getting rid of them forever... hopefully), you're saving the Geth, and in a way, defying the Deus Ex Machina's paradigm that inevitably synthetics and organics will wipe each other out. You've united the galaxy (possibly), and you trust them to do better than the past -- all you do is remove the Reapers from the equation (without unnecessary killings!), which is what you wanted all along.
But in order to do that you have to accept that you were wrong about the Illusive Man (sort of; he obviously wasn't intending to control them just to tell them to buzz off, even if he hadn't been indoctrinated; and also he committed horrible atrocities, though that can add to the complexity of the ending), which is difficult. I /like/ this. It is /hard/ to accept that you were wrong about something you've been fighting against for the entire game (at least if you were a paragon).
None of these implications are really even hinted at, of course.
Destroy All Synthetics Ending:
I enjoy the 'everything after Harbinger zaps you with a beam is an induced hallucination to indoctrinate you, and every option but Destroy The Reapers, which Deus tries frantically to talk you out of, framing it as by far the worst option, is Harbinger succeeding. If you defy Deus and destroy them anyway, you wake up and continue the fight' explanation. At the very least, the Creator (or, if this is the Matrix, Harbinger) is clearly drawing from your subconscious to create its appearance, so that alone can argue that some hinkiness is going on. It's amusing that this ending contains the only circumstance in which Shepard survives -- that can nicely support this interpretation, though I really don't think for a second that it's more than coincidence. The writers were clearly too lazy to set up anything that deep. That said, if they take this desperate attempt to justify their shitty ending and continue the story in DLC, that means /they/ were willing to accept that they were wrong, and I'd play it.
http://www.escapistmagazine.com/forums/read/9.353805-Mass-Effect-3-Ending-Conspiracy-If-you-love-Mass-Effect-and-hated-the-ending-READ-THIS-PLEASE has all kinds of justifications for this based on things that happen during the final phase of the game, but I don't take them too seriously as anything but tinfoil entertainment. I /know/ this explanation is tinfoil, but I can still enjoy watching it be defended and justified.
In conclusion:
http://www.youtube.com/watch?v=b33tJx8iy0A It saddens me that I got more catharsis and closure writing this post than I did in the whole damn game. It really, really does.