I was thinking, and I think a good setting for the next CoD would be one set during the Troubles in Northern Ireland. I'm not just saying this because I'm Irish. During the late 20th century, places like Belfast saw some of the bloodiest fighting in the world between the British unionists and the IRA rebels. I think it would be cool to play as a British soldier, and focus on street fighting and guerrilla (spelling?) warfare, both of which saw a lot of action during the Troubles. So, all that is why Northern Ireland is made for a CoD game.
P.S. Do not accuse me of being biased towards the English. As I already mentioned, I'm Irish myself.