I have an idea for eb2 , but it is probably at little hard, but it will make a new aspect in the game. and it will make it much more important to think strategic on the campaign map.

I think about having some small towns/places where people live in every/most regions. And they have levy troops and stuff garrisoned, with free upkeep while garrisoned. one or two units only.

And for invaders to get resupplied, they need to take these small towns. And you can put more garrison in there if you want. And they are just like forts, but no wall. no population or building things, but you can garrison troops there to defend them, becouse they give income to the city in the city in the region.

So they will make it much more advanced in the campaign map. becouse it is important to defend them, and it is importand for attackers to take them. but they cant just send one or two units there and take them becuse they have a free garrison of peasants or something.

I dont know really if this will work, but probaby something similar. and I just wanted to give you a little idea you maybe can work something out of, if you think it is good.