it looks alsmost like a WW3. if you'll at the scene where they're fighting in the sub-urbs you can see paratroopers in the background.
the idea of fighting right on U.S. soil is pretty interesting.
and I also like the contrast between the different missions. in some scenes, you're in what looks to be a desert, Snow and urban fighting (hell even a fortress lol). it's nice to see that it's not all based on one particular part of the world. the changes will help keep people interested it in I think.