Sorry to say, Activision cashes in rather than to innovate. Its engine has been running for too long.
The game still uses its very old engine, which clearly shows there is not much room for improving graphics. Now I don't want to be a graphics whore, but fact is that using the same textures, lighting etc. is really noticed by the major audience now, and does not go unpunished. Maybe this game will still sell a lot, which everyone will for a fact know, but for their upcoming game, they better convince the CoD fans that they still have the guts to innovate instead of making a rather lousy copy of MW2. This is like one big new pack pack update, instead of a true new game. I regret to say this as a CoD fan, but the game is not really new and feels like you have done it all before.