Come on, i could bitch about tons of things that were simplified/dumbed down for the Xbox but bashing the game for its performance is partly
What did you expect? To run like a charm? Buggy it may be, a resource hog up to a point it may be, but like it or not it has the most advanced lighthing/shadowing system bar none (yes, including ****ing FC that everybody has been mentioning on and on). And don't say it looks worse than an unrealeased product (HL2, D3 etc).
I'm very critical of ISA for many stupid things they've made to the franchise but give them some credit for at least daring to create a game with complex shadows that affect gameplay and the player can change them to his advantage. The fact that the gameplay is slow and doesn't require very high fps is not a good excuse, the lightning system however is a pretty good one.