I just don't get the outcry, personally. As Shepard, I've sunk hundreds of hours into all three games, with the last two having a fairly palpable air of desperation. I've gotten used to the feeling that Shepard's missions are going to be won by the skin of his teeth, and that with the stakes being so high, the price for success has to be proportionately high.
I just don't see how BioWare could've gotten away with giving us an ending where Shepard kicks down the door to the Citadel Child's fortress, kicks ass, chews bubblegum and ends the Reaper War. I also don't see how his or her heroic sacrifice could feasibly leave a window of opportunity open for Humanity's allies to return home.
"CONGRATURATION, YOUR'E WINNAR, ALL THE SPECIES RETURN HOME. TEH GALAXIES IS AT PEACE."
Just... No. I'm of the mind that BioWare had acknowledged that the scope of their story was so big that nobody could just walk away scott-free. Nobody could conceivably go "Welp, that's over! Thanks for the warm welcome, Humanity, we're going back to Palaven's dregs, now. Kthxbai!"
If anything, I'm rather curious to see what happens when you've got three or four species stuck in the same galactic cluster, who all need to rebuild their lives somehow, knowing they'll never be able to return home. I'm assuming there'd be plenty of casualties, what with Turians and Quarians needing dextro-amino acids in their diet, but that's part of the game plan, as far as I'm concerned.
Basically, at the age I'm at and with the culture I've gained over my years of reading and playing games, I'm actually glad BioWare didn't just flat-out give me the ending my guts wanted to see. I'm glad they basically went "Well, here's what's more likely to happen, considering what you've done" and had the honesty to do so.
What's the alternative? Your standard Hollywood Happy Ending that would've made even *less* sense? Shepard being all but deified by unimaginably grateful trillions?
Nah, no thanks.