I have posted an idea about how to implement "advanced warfare" mentioned here.
Basically USA would be very good at one thing at any given time, but need to switch strategy at their tech building to build the other branches of their tech tree. This means they will require some foresight to play and differentiate them from how EU plays further.
I like that story

I think it's better to have a entire EXP campaign dedicated to it, rather then having it take place alongside other campaigns in the main game.