It is more of an action RPG, definitely not a true RPG. That's probably another area they screwed up. If they had spent as much time on the story for the sequels as they did improving the damn gameplay and adding MP then we would have gotten much better games.
Only because of the direction they took the 3rd game, which is another one of its many, many problems. ME2 was a great game with good characters and would have led into a great end to the trilogy if the writers didn't develop an extra chromosome before writing the third game.
I liked ME2 and it had the best set of playable characters out of the trilogy. But the story unnecessarily murks things up and at times directly refutes some established plot points from the first game. I'm not saying 3 doesn't do that, I'm just saying 2 is just as guilty.
I'm one of the few who think that the first game was the best of the trilogy, not the second. The first game had a purity to it, great characters, great plot, great everything. The sequels only beat it in gameplay.
The first is my favorite as well.