mass effect 3 failed to deliver on what was promised for the entire trilogy. only the krogan stuff really accomplished their goal. there was other stuff that was kinda neat, but it resorted to one-liner callbacks to previous action, and your choices didn't have the impact that was promised. me3 fucked up one thing, and it fucked it up real big. can't think of another game franchise where a sequel renders the entire series meaningless.
i enjoyed mass effect 1 a lot. i was really into the sci-fi movie feel of it, and so was bioware. then ea happened, and they were forced into the machine to crank 'em out. i liked me2 enough, but it was essentially mass effect: the continuing adventures, and ends with "OH CRAP! I FORGOT ABOUT THE REAPERS!" me3 doesn't have the sci-fi movie feel of me1, it doesn't have the character interaction of me2, and it doesn't deliver on the promise behind the trilogy. that's without delving into the shittier stuff in the game, like the ranking system, the actual endings being shit, and the story in general being a pretty big mess.
the game part of me3 worked well enough, but no one is playing these games for that aspect. if you really wanted to play a corridor shooter, you'd just pick up vanquish like any rational human being.