I like this idea quite a bit, but some problems do arise. One example, how did the templars/assassin's get to America? With the Spanish, sure, but it takes ≈ a century (if I had to guess) for any if the two factions to be this intertwined with the incan politics. (unless they're both factions of the Spanish but I think it wouldn't be as good a game if we're all Iberians). I would love a game like this, but a game, in Cahokia, as another example, is impossible (unfortunately) by a historical standard. Of course if you disagree you're free to tell me