So what went so wrong with a series that I enjoyed so much right up to the very end? Hell, even 10 minutes before the final credits rolled I was completely in love with how things were going so it wouldn't have taken a masterstroke to make me perfectly happy. I would have been satisfied (if not exactly blown away by) a simple ending where Shepard gets onto the Citadel, hits a gigantic red button and is blown to smithereens while the Crucible destroys the Citadel and all the Reapers at the same time followed by a few minutes of cutscenes where a small glimpse of the fate of each of the named people in the series is played out. It wouldn't have to be a happy finish necessarily; given the focus of the series on sacrifice and the price to be paid for freedom I would absolutely expect some tears and sorrow at the end. Instead what we got was a whole bunch of nonsensical answers, bizarre metaphysical mechanics and a final choice that seemed like it should be of pivotal importance but which matters not at all.
After some consideration though I have come around on the ending. Not that it wasn't bad... it was bad. Rather it was bad for entirely different reasons than I thought initially. After all, the ending made no sense, but the entire *series* made no sense.
Why was Sovereign around in the galaxy? Why do the Reapers sit around a thousand light years away from the further star in the galaxy?
Why do gigantic invincible spaceships with unstoppable lazors spend all their time sending zombies at their enemies? You have unstoppable lazors!
Why are synthetics engaged in a million year long quest to annihilate organic life with the sole purpose of saving organic life from being eradicated by synthetics?
Why is it that every time anything interesting happens there is something critical for some soldier with a rifle to do? These are battles between high tech space dreadnoughts and yet every time I have a pivotal role to play with my freaking pea shooter.
Who the hell cares if the krogan are coming to fight the reapers? The krogan are dudes with trucks and shotguns! We are fighting freaking gigantic alien spaceships with lazors and you have a SHOTGUN and a TRUCK? Why don't we just recruit some hillbillies and win this war right now?!?
Nothing makes any sense from start to finish so the fact that the ending is a completely nonsensical collection of rubbish is absolutely in line with the rest of Mass Effect. If you wanted logic you should have gotten off the bus a long time ago. What the ending should have had and what ME did right throughout the series was present difficult choices and get strong, visceral emotional reactions. During ME3 I was absolutely riveted when Mordin sacrificed himself to destroy the genophage; I was screaming inside at him to stop and get his ass back down from the tower. I would rather have you alive than all the crap pile Krogan with their shotguns and trucks Mordin! I was horrified when Tali threw herself to her death when I chose the Geth over the Quarians - it was RIGHT, damn it, but I had to watch a friend commit suicide because of my choice. In short the first 95% of ME3 was all kinds of awesome and that was what the ending needed to have. There didn't need to be any more choices necessarily, just watching the results of previous choices and seeing scenes of gutwrenching power. Bioware can do scenes like that; they have done so successfully throughout the ME series.
The whole thing ends up feeling like the Matrix. The initial movie made no sense but we had hope that somehow they would take a creative mess and bring it all together in the end. Instead we found out that they had no idea what they were doing and the whole thing was just a collection of entirely random junk that managed to be awesome by sheer luck. The ME series is the same - nothing makes any sense but we held out hope that somehow in the end Bioware would find a way to link all the bizarre and insane threads together into a cohesive whole despite the fact that they had displayed no aptitude for doing that at any point. We loved the heroes, we loved the game, and that gave us false hope for a miracle. There was no miracle and all they could possibly have offered is closure, an ending. They failed at even that.
The fighting was great. The choices were great. The emotional impact was great. All you need to know is that when you are making your final run to the beam you should shut off the game right then and make up your own ending. Whatever you come up with is going to be better than what you will be offered if you actually play it out and that is a shame for a series that did so much right. It is sad to have the memories of hundreds of hours of awesome soiled by 5 minutes of suck.