I think we have to look back at when the game was successful and why.
In the old days you had high noble densities so nobles were living cheek by jowl with one another. That meant that you had plenty of neighbours to go to war with, even if the only outcome was a couple of regions changing hands, and there was enough internal activity to make rebellions and secessions relatively common. That made the game interesting.
The problem now is that, even if every realm had a density of 2 nobles per regions, the maps are too big for the number of characters in the game. Take Dwilight for instance: even if every realm spread out to 1 noble per region there'd still be room for each of them to be surrounded by rogue regions with no direct human neighbours.
The best solution is to have realms squeezed in tightly next to one another with a decent noble density, rather than have them spread out and each realm left overstretched on its own with no capability to go to war.
If you were to confine the entire noble population of Dwilight to just 6 duchies then conflict would pretty much never cease.
So what I was thinking about was how do you force nobles to congregate in one area where the density will be high enough to drive conflict and war?
The current solution on Dwilight is monsters. But that results in lots of realms left isolated and playing pure PvE - Luria, Fissoa, Madina and D'Hara are all realms without any human realms they can realistically fight. And the temptation is still there to expand slowly and stretch yourself out further, leaving you even less capable to play anything other than Realm Management Master.
The advantage of a hard limit (2 nobles per region minimum or you won't be able to hold onto it) is that it would force realms to consolidate and prevent expansion unless you had the noble density to support it. In practice, that would have to mean war with neighbouring human realms. So somewhere like D'Hara (a realm I play in) would be forced to make a choice: either stay at a fixed size surrounded by rogue regions forever, or relocate to an area where there are other realms to fight (e.g. the North East region).
The same would apply to every single continent. Nobles and realms would be forced to congregate together by a hard limit whereas right now the softish limit (of maintenance, etc.) means that it's still possible to coast with more regions than you can realistically cope with at the expense of war and other conflict that makes the game exciting.
Something like this would be a big change but I think a hard and fast rule would be much more effective in forcing an improvement in gameplay than just giving realms the opportunity to duck hard choices by switching to PvE and stagnation by default.
