Wouldn't that be cool if factions emerged or re-emerged mid-campaign. Like the Mongols. Or say you kill off a faction but they come back later in the game. It might be possible to have them emerge based on specific conditions like for an example the capital city of the killed off faction revolted and thus remerged back into the game. It would be really ok if this was possible to mod into a game. I do not have any modding experience but if you guys don't feel like doing it I could make it happen. That is all I have to say on this matter.
"He alone, who owns the youth, gains the future."
Adolf Peter Hitler