Those are some pretty good points.
I feel like control of non-fortified regions ought to me more fluid. Right now takeovers are just a bunch of either meaningless violence where even the whitest of knights suddenly turn into violent hooligans, or endless freedom celebrations that set regions awash in ale for a week. And if the invaders aren't taking over, they're usually just burning things to the ground, slaughtering hundreds of peasants in the process. War is simply too devastating to be on the losing side, so most realms won't risk it unless victory is all but assured. Other realms just simply can't afford to take much land from their neighbors. Realms should be able to benefit from occupying land without actually taking it over or looting it to cinders.
