I've got a suggestion. Not sure what you will think of it tho. But personally, I think that it would be cool if the map was just Swadia and the plot of the mod was some type of civil war. Also, Nords/Rhodoks/Vaegirs would be a part of the mod, but not at first. If you have ever played Medieval Total War (i think it's that one) the Mongols come into the game after a little bit and slowly march through the lands. This would be cool if the other factions did this. They would cause even further chaos in Swadia.
What do you think?
EDIT: And I know you already had the civil war idea, but I just wanted to emphasize the chaos and confusion going on in Swadian territory. Maybe some lords wouldn't take sides and would try to stay out of it or something like that.