Everyone's probably thinking it, so I'm gonna say it: Where are the Russians?
Replacing the Russians with the Canadians?!?! That's just darnright sinful!!! I was looking forward to this game because I'd be able to play an awesome graphics version of the Mosin Nagant of the PPSH... Nope, total and complete letdown.
Other people have other complaints, but the no Russians kill the gameplay. They're the best part of Call of Duty and they're gone. They might be able to win me back with an expansion pack or something, but until the Russians are back, no more COD for me.