May I make a suggestion to the 4 FOs? How about taking the "bad guys" from the new sets and keeping them together as a non-role-playing faction from an unmapped part of the world? They could be used as an invasion force when you want to provide some conflict without upsetting the balance of power between the role-playing factions. Additionally, they could be a destablizing force as well, making for some interesting dynamics with improper treaties with one faction over another, etc. They could easily be kept distinct from the Outlaws, who just want to live unfettered in chaos and profit, by making them unified in organized aggression such as the Assyrian, Roman, or Ottoman Empires. I think this is an idea worth discussing.
Some very interesting ideas there, I'm just not so sure how well they would work.
The map, factions, and story/premise of Roawia are pretty much "set in stone". Of course, things will change and the story will continue to develop, but adding another substantial force, or faction, (whatever you want to call it
) would seem to me to upset things rather than make things more interesting.
The factions have had balance upsetting and interesting alliances and treaties before now, for instance, Lenfald and Loreos formed an alliance some time ago, but that didn't stop Garheim from maintaining its global points lead. And when it looked like the outlaws were going to be "purged" in the GC3, the KC turned the tables on the "good" factions and gave the outlaws a victory, and now we have a large-scale war in what was once a strongly united kingdom.
This is just my personal opinion, I'll put it before the KC for you.