I wouldn't say it will be huge, but it's not a bomb or flop. You all forget this is a Wii game, and you need at least three months to see if a game will be a hit.
Also, the CoD4 engine is scalable. Treyarch was very clear on that, so the game did not use a custom engine.
EDIT: Remember when Boom Blox was a flop?
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs