In medieval times, Wales went to war with England in order to gain their own monarchy(I think...). What I think is, how about we have a king of the wilds , too? I understand that, obviously, the king of the Northern Kingdoms would have the most influence on Altera on the while, but a king of the wilds would:
Promote RP banditry
Add more danger to being in either realm
More immersion in a Skyrim kinda way.
What I mean by my final point is this: The Stormcloaks controlled half of Skyrim, the imperials the other. What if Altera was halved in almost the same way?
Currently, I don't really think that some houses actually have anything against each other, they're just going for the crown because they think they have a chance. Basically, I just think there should be some more politics involved. Forgive me if I'm wrong, I just haven't seen any myself.
Back to the king of the wilds thing. I think it would be great for separation between two main groups, rather than a lot of them. It could encourage larger wars because people would be encouraged to join one of two sides. However, it doesn't necessarily have to be the wilds vs. The NK. Marks choosing the side of their town/house could have their town WorldEdited to a different location, on one side of Altera.
There are quite a few ideas there, don't feel forced to use them all as one(if they are used
).