Indeed...as i play always on Huge Scale...most of Ai settlements are on the lowest level of population (<500), especially when they are near the frontiers or when the ai-faction has a longtime war to fight.

it would be nice, if this system of re-adding population would be adjusted for huge scale.

another annoying thing due to the low population is, that if i capture these settlements, they got a awesome boost in pop-growing-rate (6-9% / turn !).
i think this is caused by the partially advanced infrastructure of a once big city, which population is now depleted.

the population grows faster than i can build my factions buildings to keep them calm.