I think the division of Okinawa in three provinces aims at reflecting the three kingdoms that fought in the island, I personally think it gives actual depth to the political situation of these territories. For example, the division of Japan in multiple territories might help better to feel the struggle between local feudal powers who came to rise. For Korea , until the 7th century the country was divided and making just a few provinces wouldn't enable to simulate the possible regional divisions, the country wasn't a monolithic entity throughout its history. Well that's just my point of view I'm not a dev after all.
True, but these counts make the map unbalanced.
I count 63 provinces in Japan (just the red provinces, not counting either tribes or the southern islands). That's more than France (52, which is k_france + k_aquitaine + d_flanders), who had around 9 million people in the year 1000.
Population estimates for Japan of the time average around 6 million. So Japan should have had 2/3rds of France's province count (which is 35), but instead it has 1/5th more. That's 45% too many provinces.
Now, for Korea (just the blue parts) there's 43 provinces on this new map. I cannot find Korean (Goryeoan) population estimates
anywhere, but I did read that the population remained fairly homogeneous throughout the ages, with very little immigration. That's about the same case with Japan. So, I now make the assumption that the ratio between the populations of the countries stayed sort of consistent over the past 1000 years. 76 (N+S Korea) / 126 (modern Japan) * 6 (medieval Japanese population) = 3.6 million people. 3.6/9 (France medieval population) *52 (France provinces) = 21 provinces. It has more than twice that on this map.
I know I took a couple leaps of logic here. I know I should have counted holdings instead of provinces, but I cannot see holding counts in the screenshots. I know that there's little chance for France to ever get in a war with Korea (I probably should have compared to Indian regions, but I doubt I would have found population figures there if I cannot even find them for Korea). But this should at least demonstrate that something is off. This way, a ruler of Korea gets twice the income of the ruler of a similarly-populated country in Europe. They can have twice the amounts of grand tournaments, build twice as many castle towns, etcetera.
To offset these population imbalances, each Korean and Japanese province would need to be about twice as poor. That in turn would make any single one of them less worth conquering, and grant them a military advantage while it also slows down warfare.
That's why I think there's just too many provinces, and that a lot of them should be merged.