But, why not? What was so terrible about it? The deus ex machina?
-We were given a massive info dump that didn't make sense in the last 5 minutes of an epic 3 game, 100+ hour space opera.
-It was full of plot holes and nonsense (How did Anderson get ahead of you when he followed you up? How did TIM get behind you when he should have already been there? How did you squad on Earth get to the Normandy? Why was the Normandy fleeing?)
-The 3 endings were virtually the same. The colour was different and some things change but it all boils down to: Relays gone, Reapers gone, Citadel destroyed (and all those who were on it dead), Normandy (and crew) stranded, Galactic fleet stuck in Sol system.
-We never got closure on our choices. Yes, our choices did make a difference during the game (Did we cure the genophage? Did we get back Rannoch?) but we never get to see or even know of what effect it does have and in the end, doesn't even matter (Quarian fleet in Sol, large amount of Krogen including Wrex on Earth).
-We were straight up lied to, as late as February of this year. We were told that our choices would matter in the end and that we'd get answers etc and not just a choice of A, B or C with a bucketful of speculation for everyone.
Also a few more:
-No ability to argue against the starchilds stupid logic. We have proof of organics and synthetics getting along, why can't we use that evidence against him?
-Why can't we just say 'Screw you' and take our chances? It'd mean the EMS system actually had a use (other than determining if Big Ben stands or falls) and would be something I think Shepard would do. The EMS thingie even says, when it's t full, that the chances of victory are even. It means, at full preparedness, the united fleet are just as strong as the reapers and stand a chance of winning.
-A minor one, but there isn't a 'everyone dies' ending. It'd have been nice if there was an option where the reapers win, you don't break the cycle. It'd then show a civilisation 50,000 years in the future finding one of Liara's time boxes and seeing her message and then cutting to dark space and then the reapers light up again and start making their way back tot he galaxy.