But, thinking of it, won't the game, as it is now, be quite a downer? Basically it is US+UK, and quite possibly the rest of the western world versus North Korea, Iran, China etc. IMo, that is overkill, and we should leave room for interesting, unhistorical events.
The best idea, IMO:
Let us create different campaigns. One is the default "realistic" one, the other a US gone bad, a third a ressurgant Russia claiming former Soviet land and so on.
Other campaigns can be set in the middle of WWIII, with whatever situations that might hold, so that the player isn't forced to "wait" every time. (Think of the "Blitzkrieg" scenario compared to the "Road to War" scenario in HoI)