Oh please no. Please just no.

Providing a Chinese interface means just one thing. Hordes and hordes of Chinese players will storm the JP/EN data centers, and they will openly chat in Chinese using Shout and they will destroy the game environment. They will bring RMT vendors to the JP data centers and they will cause inflation in the economy.

This had all been proven by the Taiwan World of Warcraft servers. Don't let it happen to FFXIV.

If the Chinese want to play the real FFXIV. Learn English or Japanese.