I think you picked bad examples. Usually the AAA games push graphics and gameplay forward. The first time I played horde mode in Gears2 I thought I can't believe no one has done this before. I think the storytelling of COD4 and COD:WaW is a leap forward from similar style games.
When I think generic, I think stuff like Haze, Timeshift, Conan, Golden Axe. The lower budget games usually try to emulate the more creative and successful AAA games. On the cheap side, I thought Gripshit, Poker Smash, and the Simpsons game has been creative low budget games.







