Around 4 regions away from the capital. Once your region is farther than that, it is pretty hard to maintain.
Yes, and this is my point. On Dwilight, with its geography in particular, that really limits the ability of realms to form in a way that provides conflict. Let's look at a couple of examples:
D'Hara - The furthest it can expand west is to Paisly and Paisland, and only then if its capital is in Port Raviel. The furthest it can expand east is the Desert of Sillhouettes, which means that, even if Swordfell's capital was in Balance's Retreat or if Luria Nova's capital was in Askileon, there's absolutely no way in which D'Hara can takeover and hold any regions which another realm would want.
Arnor - Pretty much the furthest it can expand away from Springdale is to Taishan/Croton. Those are also the only regions close enough to another city for another realm to be able to hold so those are the only regions that any wars can be fought over. And how likely is anyone to fight a full blown war over a couple of rurals? It's certainly not going to be something that happens on a regular basis.
There are loads more examples like those two. The geography of Dwilight means that, even with the best will in the world, lots of realms can't possible expand far enough to be able to have anything worth fighting with a neighbour over. So the distance limit and the geography put together end up starving the continent of conflict.
At the very least, reducing the distance penalty for region control would make it slightly easier for realms to expand into places that would bring them into conflict with other realms - and, since we already have the rogues to prevent realms from spreading themselves too thinly, the distance penalty mechanic really isn't as necessary as it is on other continents.
