I agree with Mythos' view on the matter. Typically, when you try to span ridiculous time lengths, you will merely find people complaining because A, there will be complaints from people who dislike the fact that they have never heard of the Hurrians nuking the Canadians while the latter civilization is stuck in the Iron Age, or B, this game was not able to frame the epic timespan of history, and has too few cultures. Age of Empires tried something like this, and it wasn't quite successful in my opinion. There were too few ages to cover about ten thousand years. Even then, it seems likely that all that will happen is the project will be aborted with as much work as would have to be done.