We have a Japanese Empire style and a Chinese Empire style faction in concept already worked out, along with Native American, South American, Balkan, US Colonial and a few city state Euro style ones planned.
Plus we have two factions we didn't release in the last update as Frenzied needs to find his creative mojo in tooling them out.
The problem is thus, the team is more or less a one man band (I write fanfiction and beta test, barely code any of the stuff) and the time being we really need to do more than just keep adding faction after faction.
If we had a bigger team at our disposal with several coders, we could pretty much make this mod an awesome thing. But until people volunteer for now we're pretty much working on improving what we have to a certain degree.