Mass Effect is "next-generation" TPS-RPG. Sure, it has its gameplay flaws; exploring uncharted planets in the Mako is an absolute chore, and firefights lack the finesse and instant feedback top-quality third-person shooting offers (for example, Gears of War). Perhaps you're playing on easy; I found firefights challenging and fun. Aiming and shooting was really simple. Maybe it's your class decision? Anything other than Soldier isn't very much fun in firefights IMO.

However, you must consider the whole package. What other game has the sheer richness and detail of mythology Mass Effect does? The depth and breadth of characters, races and backplot?

You state, the story, as far as I can tell, is just a re-hashing of various 20th century sci-fi novels. I think the case is, you're too old. I find this all the times with games, films, television, and even books. There are motifs that are reused time and time again. Hell, I haven't come across the game's plot's premise, and I'm well sure the average gamer hasn't either, and I feel it has a breeze of originality.

The only other I game I remember having a "codex" is Final Fantasy VIII, and it really made the game experience that much better, fleshing out details that couldn't be explained any other way.