Right, well then:
First off the biggest gripe is the characters. To the person who said this game took RPGs to the next level, I can tell you've never played Planescape: Torment or the Baldur's Gate series.
If you had, you'd know that the the older RPGs had characters with actual personalities. When you did something in game and they didn't agree with it, they'd actually speak up. When walking around they'd argue with each other (Viconia + Aerie springs immediately to mind). If you pissed them off enough they'd actually leave the party until you had fixed whatever it was that made them leave. In the latest crop of RPGs this interaction just didn't exist. In Mass Effect, there's the situation where you have to choose between saving the posessed colonists on the planet with the big mind controlling plant thing, or killing them. I started slaughtering them wholesale and no one said anything. No matter what action I took, they never really say anything.
When walking around they were stone silent, there was no real banter. If you wanted to get to know the characters you had to go up and talk to them in the ship. They turned character interaction into a god damn time sink. Every single moment that my friends would show me of this 'awesome dialogue and interaction' was on the ship. That is not a step forward, but one giant step back.
Combat was ok, but horribly hampered by the buggy cover system and completely glitched squad AI. "Hey, you go save the day, I'm gonna spend the fight shooting at this wall! Have fun!"
Graphics weren't anything special and yet caused noticeable framerate drops on the 360, which boggles my mind honestly. The planet roving was incredibly bland with the same mountainous terrain over and over with the only differences being the colour pallete used.
The story itself was just a hamfisted affair that tried desperately to be epic, yet offered no real serious or interesting plot points.
All in all, the raw shallowness of this game puts it more in the realm of the first final fantasy games than any sweeping, forward looking RPG. I challenge any of you to try and present points on how Mass Effect "advanced the genre."