Txurce
Deity
@Sneaks
It was an easy change because there's a direct comparison between Korean and Ottoman traits.
- Ottomans: +1 specialists
- Korea: +2 specialists, +2 great improvements, 1 free tech with each science building
The Ottoman trait is very powerful since specialists are more accessible and useful in VEM than vanilla. The Korean trait was significantly better than the Ottoman trait, so by association it was too powerful.
I also buffed the Turtle Ship. It's on an earlier tech, upgrades to a more powerful unit, and gets +50% vs cities. Korea is the only civilization who can start their Ships of the Line with more than 30xp.
Buffing the Turtle Ship by giving it 50% vs cities goes against the essence of the unit, and the civ. This change is philosophically the opposite of what you did in switching Denmark's Ski Infantry for the Jelling Stones.
Korea doesn't get one free tech per science building - it gets the equivalent of a vanilla RA boost. And the "great improvements" are practically limited in number.
Unless you have played with Korea and scored significantly better than you have with the Ottomans (or Babylon), you have no reason to conclude that they are OP. As you often note, the game's mechanisms are pretty complex. That you didn't take the time to play a single game with Korea before altering it threw me for a loop as well.
Apparently you view the DLC as pretty much a failure, with the signature trait needing a nerf and the UU needing a total overhaul. But for me the result flattened Korea's impressively conceived, singular identity, and I couldn't disagree with it more.