The problem I see with that is after Hawkwing died, his Governors and Generals all fought for every scrap of land they could claim, and once they held it, they held firmly onto it. Their heirs have been letting it slip.

One prime example is Andor. We're told that Ishara and her husband fought to keep the city, then the leagues around it, and then pushed to expand the borders until they had one of the, if not the, largest nations in the Wetlands. Her direct heirs had to fight too. IIRC, we were told that by either Elayne or Dyelin, either of whom has enough claim to be a serious contender for the throne, so it's common knowledge in the nobility. Why would successive generations just let that slip away?

Why send Queens Guard troops to Baerlon (a small mining town) but not send them farther down the road to the Two Rivers (a town that produces a world-famous tobacco crop)?

I do agree that the White Tower's push for maintenance of the status quo probably hurt humanity's expansion via war, but I'd still expect to see Andoran farmers pushing north into the Caralain Grass. There are plenty of rivers, and they could be secure in the Black Hills if they wanted defensible positions. Soft expansion by virtue of population movement into unoccupied space should have filled the map.