I'm ok with nuanced, but i also like the blunt force trauma approach: no lord = no region. Its ridiculous that realms can control and harvest the resources from an absurd amount of regions without the nobles to actually manage the regions. Morek and Riombara are both perfect examples of how realms have pushed this beyond the extreme, into the absurd.
So, yea, add some influences to help drive realms toward a more even expansion. But also add in the blatant restriction that without a lord, the region will eventually go rogue.
