My assessment would be:
1) City region populations are still too high (even if you assume they include a hinterland outside the core of the city itself)
2) Non-city region populations need to be greatly increased
3) The continent square mileages should be completely redone based on the look of the continents and the populations
So the Colonies feel, to me, as though they're roughly equivalent to medieval Ireland in both size and population. So they just need the population rebalancing some and the size of the continent massively shrunk.
Dwilight, on the other hand, feels vast so its official size is about right. So, for example, Greater Luria (e.g. Luria Nova plus the Shinnen peninsula) feels to me like an area broadly equivalent to medieval France. It should have literally millions of peasants living in it and Giask should be the equivalent of medieval Paris. The entire continent should have a population of over 30 million peasants based on its size.
The East Continent and Beluaterra, on the other hand, both feel to me as though from north to south they're about the same length as medieval France or Germany (only a lot thinner). So they should also have populations to match.
Alternatively, you could say that the East Continent should have roughly the same population it has now and therefore make it follow a medieval Britain model of population density and land area.
