You think you're sick of World War II shooters? Spare a thought for Infinity Ward! They were sick to death of World War II shooters, which - as you could have guessed - is exactly why they went and set Call of Duty 4 in the modern world. From an interview in this month's Developer magazine:
Call of Duty 4 was Infinity Ward's third Call of Duty game, and as such we approached it knowing we needed to do something fresh. We don't want to pigeonhole ourselves any more than we have to, and many members of the team came off Call of Duty 2 promising never to work on another WWII game....We don't agree with some critics who say that WWII as a genre is dead, but we couldn't muster the same passion for the subject that we had in our first three WWII games
Lucky for Activision Treyarch can muster WWII passion at the drop of a hat!
Infinity Ward On Call Of Duty 4 In Game Developer Magazine [Game Developer, via GameSetWatch]