A while back, some of you may recall "Conquest: Nation Domination". It was an interesting concept, but had a major flaw: The system. There was no way to keep track of everything going on, but I persisted, and redesigned the whole thing.
Original Thread:
http://www.dakkadakka.com/dakkaforum/posts/list/385504.page
This will instead be turn based. Each player will make five or six "moves", which will consist of anything from taxes and banning alcohol to to new technologies and invading neighbors.
Now then, the parts to be discussed:
Should players make their own nation still, use a set of pre-made ones, or use real world ones?
Making one's own nation provides the opportunity for great personalization, but it also makes natural balance difficult. This can be avoided with pre-made or real-life ones, but they are much less personal.
Once that answer is found, and players come along, then there will not be much to plan, save for our starting era.