Why would it suck?
Because it's a mirror of every COD since COD4. Instead of MW2 + MW3, they could have released MW2 NOW and make it a REALLY good game.
Skyrim will have an entirely new setting, with features that actually set it apart from Oblivion. What's the new stuff transitioning from COD4 to MW2 and MW3? Guns... perks... and all of them are synonymous to something from the previous game. Not exact mirrors, but there is too much recycling going on.
Also, multiplayer-heavy games like this need longevity. Patch it every 3 months, I don't care, but make them last a good amount of time, and once you see the population go down, start on a sequel with improved AND unique features that separate them from the previous title, gameplay-wise.
The only reason I'm "acquiring" MW3 is to put an end to its single-player story. After that, hello 500 hours of Skyrim, Sword of the Stars 2, Diablo 3, and Mass Effect 3.