If that is the main issue, the solution is easy: Limit the number of regions that realms can absorb in a short time, irrespective of realm size. So if you can only take 1 or 2 regions before half your realm blows up in unrest, you'd go for peace after that, and ready for the next war to take another 1-2 regions.
How would people circumvent this (because I know they will) ?
Well, first of all, they'd resort even more to driving regions rogue, rather than taking them.
Second of all, they'd make sure to have a large coalition of realms so they could actually take over as many regions as possible (thus making gangbangs much more the thing to do).
Third of all, it depends greatly on what you mean by "blows up in unrest"; if it ramps too slowly, then people will just sic their diplomats and courtiers on it, but if it ramps too quickly, realms will just disintegrate. Also, how long would the unrest last after the third takeover?
In general, I'm not a fan of this idea.
Actually, I'd say that since we've already
got a package of changes intended to improve the warfare situation discussed and on the slate for being implemented this fall and winter, we should hold off on trying to make any more major changes to the way war works until after they're in place and we can see their effects. Some of them are going to have very large effects on the way people conduct warfare in BattleMaster already (or at least, if they don't, then we've done it wrong!).
