me1 was a promise which has never been kept. the game by itself sucked but we've had nothing like that before. me2 took away all the crap (meaning "almost all the game") and left a sleek, essential shooter with some funny cutscenes (i had a good laugh with the verbose krogan and the renegade trigger, if you know what i mean), one or two outstanding characters and better, much better planets, mostly because there was no mako anymore.
all i would have wanted from me3 was more stuff like krogan planet, or even better the one with tali whose gimmick is just "don't stand in sunlight". it's beyond human comprehension how that bunch of retards couldn't deliver even so little.
Mass Effect was an idea that even the first Mass Effect didn't fulfill. Even by the time it made it to the shelf it'd dropped two of the reasons the series was even called Mass Effect to begin with. Gone was the whole reason they went with the dialogue wheel in the first place, and gone was having to make choices about what missions you went on. The one core idea about how your actions would have an effect on things was the idea of throughlines between games, but then that's something you needed to wait until the next game to see if it was actually a thing...which it turned out not to be in ME2.
In actuality Mass Effect 1 was a pretty bad third person shooter. It had pretty terrible corridor style level layouts, the opening area of that game was a pretty rude awakening from what I thought the game was going to be from following its development into what the game actually was; and bland tiny open areas. Can't really say there was anything new about what was actually in the game. There was potential for all the different elements at play, there's vastly more interesting ways they could have taken it even within the realm of being a third person shooter.
In hindsight I'm kind of surprised neither Mass Effect or Mass Effect 2 were just a sandbox style game like a GTA. Sandbox kind of seems like what they wanted to do, but like many things in ME never committed to. Would imagine if they used Pandemic Studios' Zero engine they could actually have had some good driving, and stuff like the sandworms seems like an idea made for a sandbox.