I've been saying this repeatedly, but I'll say it again. I think ME2 is leaps and bounds beyond the stale, generic muck that ME1 turned out to be.
Those of you criticizing the removal of the original's so called RPG elements should take a good hard look at what those "elements" actually were. We got a horrid and dysfunctional inventory system, that made us do a full fucking inventory check every time you'd want to loot an enemy's corpse - something every RPG must have.
We got a superficial weapon and armor upgrade system, which was tedious to use and provided no real meaning or benefit.
Oh! We also got a plethora of mundane and cookie-cutter side quests, all of which for some reason took place in nearly identical locations.
The gameplay was equally shit; from the annoying ammo management system to those horrible, horrible MAKO driving sections.
What ME2 did was simply get rid of these things, as in their current form they simply had no purpose, being a mere token RPG presence. Instead the game embraced its action aspect, to great success. I'm not saying that they couldn't have had improved these things ans mold the sequel into a proper RPG, but those features were simply useless in their current state.
As to the story, ME1's felt simply uninspired to me, just another Bioware game where you have to save the world with your bunch of buddies, BUT IN SPACE! There were no difficult moral choices, no shades of gray, no atmosphere.
Whereas that of the sequel was much more brooding, filled with difficult choices and answers. I have to say that I found myself much more immersed in the plot and atmosphere, and it was one of the two games where I actually didn't reload the game when I made a bad call in the story, the Witcher being the other.