Eh I disagree. MW3 feels the same as playing MW2 and the original MW. They are essentially the same games. The maps in MW3 are also terrible. They are all super small and just poorly made.
I didn't play anything before Black Ops online, but seeing how COD4 is praised, I don't see how it's a bad thing. The maps aren't too bad when you play more often and get to know them. They definitely are small though, I rarely played anything but Ground Wars on BO, now it's the other way around lol.