This should happen naturally anyway, since people should be slowly gaining a lordship in the better regions, depleting the pool of available nobles to run for the lesser regions.
So, when a character sees an election starting, and thinks "hey, it would be better for me if I could run this region", at which point exactly should he not run because it hurts the world setting? Is the counter reset every time a region goes rogue?
Basically, you're saying a character should not have the right to run in an election if he won a previous election a short time prior. Which, on the face of it, would be a justifiable rule of the game, if it were a rule of the game. However it's not one, and it's not right to tell people they're abusing the system when they simply click the buttons that the games gives them.
Remember what Delvin said about the oath to the people that you abandon when stepping down as a Lord?
To address that point, there is an honour drop to leave the Lordship of a region, so that is taken into account game-mechanically, and it is also taken into account in RP in that a character who has had Lordship to multiple regions cannot claim a long history of leading one particular region.
