[Cossix]

That's not really a problem that's existed in most 3d games though, is it? I mean if you look at the first person shooter genre, sure they reuse a lot of enemy models (and sometimes they reuse prefabs), but there's not a lot of repetition in the level design. Also the Ratchet and Clank platformers didn't really have a whole lot of backtracking through the same part of the level unless you were hunting for optional stuff. They had several paths in the levels to complete other objectives, but that was about it really.