Maybe we can just have more events about China instead of just have China in game. The existence of China can be some like....err........Aztec

Events like:
1, Mongols get reinforcements from China...(And maybe they start to equip cannon special troops.

)
2, Pope require you to support investigating China.
3, Some random guys from Rome claims they are envies sent by Pope to China requiring your gold.
4, China demands a gift from you.
5, Rulers with business focus exchange teas and chinas with China.
6, Some Chinese immigrated to your holdings.(+income, +event to provide taoism buff or something alike)
Decisions:
1, Send a raid troop to China.(And then get a vengeful doomstack sent by China in return... )
2, Send gift to China(And recieve something random in return)
Or something more fantastic:
1, Plagues happened in China -> Sick people from east appeared in your holding -> They dead -> They are undead! -> Massive Chinese zombie doomstack appeared in the east -> You need to send troops,doctors and a cat to find that bonsai tree in Japan to cure zombie virus