I cannot recruit units in Japan as Korea, nor I can in Korea as Japan.

This makes a lot of sense since it really isnt logical that Koreans are going to train Japanese citizens to fight other Japanese. Maybe if the place was occupied for 50 years and was completely incorporated and assimilated into Korea culturally. However I still don't see Koreans fighting against other Koreans if the Japanese invaded Korea or the other way around. Japanese hated Koreans and Koreans hated Japanese in these era.

Ok. Here are some suggestions.

1. Adding extra geographical features: Dok-do and Ulleung-do. These islands were inhabited ever since the ancient times; Shilla eventually conquered it but Chosun kingdom forced people out of the islands due to high piracies around the islands.

For the game purpose, we should make These two islands have a high tax base islands with two trade nodes. This would make the naval game very exciting and the map would feel definitely more filled in with that huge sea between Korean and Japan.

2. Add town in Jeju islands. Jeju Islands were inhabited by quite the population. Adding town will only make sense.

3. Allow mercenary recruitment in Japan as Korea. There were a lot of mercenaries in Japan during Sengoku era. Koreans would have used those mercenaries had they invaded Japan.

4. Add graphical details in Korean Geographies. They just look too plain compared to Japan.

5. Make Tsushima islands able to recruit units when Korea conquers it. Tsushima islands have been in good relations with Chosun, so it makes sense that their citizens would fight for Koreans.

6. Make Korea have high corruption (or of some sort in equavalent). Chosun suffered a great deal of government corruption during Sengoku era and was their ultimate demise that led to Imjin. The government was too weak and economy was completely hopeless.

7. Stronger Pirates. Sengoku era was the golden age of piracy. However the pirates does seem too weak in the game. Chosun abbandoned Ulleung-do and Dok-do because of pirates. Sato islands were often left burnt and looted due to pirates. Pirates need buffs!

8. Ming and Northern tribes: Oh man with these elements, invading Japan would be much harder as Korea. One of the major reasons why Korean never couldve invaded Japan.

9. Smaller Korea... It's way to big compared to Japan. Really it is. Takes like 5 turns to get my units recruited in Capital down to the southern Coast. And 5 turns takes forever with that 50,000 factions down there having an orgy.

10. Make the unrest harder to get rid of. I don't think Japanese towns will be happy getting occupied by Korea governed by only 400 militia with swords. Same with Japanese occupying Korea. Oh man during the Injin invasion Koreans were so unhappy with Japanese. Koreans never cooperated with Japanese; they would kill themselves rather than cooperate.

11. Korean voice actors... idk how you would get actors to voice out all the sentences... However I am sure there are Korean gamers with good voices willing to do it.

THESE ARE ALL SUGGESTIONS. I love your work; I am really excited about Ming upcoming. Hope you add Taiwan as well, and filled them up with pirates ;)