Defcon 2 should definitely be the same idea on a real 3d globe. The idea was already nicely done in X-COM: Ufo Defence. Play it and see.
The 2d map has its natural weaknesses and warpings. For example the nukes from Russia to USA would in reality pass over Arctic. The Arctic sea is also.. Well, you know this stuff, would be cool with a real world.
Maybe you can steal the nice model in main menu demo screen?
As for Defcon1. There should be a main chat or a way to discuss with players who are not in a server yet. Using this you could find the company you like faster. This could later also be used to make a moderating system, as players could ask for help from an authority.










