The thing is Mass Effect 1 was the first of it's kind. It's pretty much one of the first game to meld rpg into a shooter and it came out great.
not to mention the graphics was ahead of it's time.
And the writing was straight up Honor Harrington awesome pulpy trash, the perfect balance of down to earthiness (lol) and epic dumb drama.
The balance was off after that though and everything went downhill.