Excellent points. I think under this feature they still can expand, but they will need to acquire the manpower to do so, which will incentivise players to recruit their friends, and to try to woo nobles away from other realms by offering them a lordship or a lower tax rate.
I don't think this way of thinking works. First because it breaks immersion. I'm all for recruiting friends, but it should'nt be to achieve IC goals. IC goals should be achieved by IC means, and you should recruit friends because the game is fun. Secondly, in practice it still ends up in a vicious circle: "We can't go to war because we don't have enough nobles to maintain our own regions. We should recruit some friends first" - "My friends won't come to play in this boring realm which hasn't been at war for ages!".
Given the feedback on this FR, it can be changed so that low-density regions don't have to go rogue necessarily, but just suffer decreased morale, production. So one or two nobles can keep the region loyal, but it won't reach 100% stats.
Anaris has already announced changes that will make it possible to keep a region at middling stats without having spiral out of control. When that is applied, then something like this can work. This could mean, for example, that a region without knights would be less profitable and easier to take over, but wouldn't run a deficit or go rogue on its own.
