Psionics fit beautifully in an OA campaign. Psionics are definitely appropriate for Chinese philosophies that see mind and body as one. The system also better fits Asian religious beliefs than the cleric system in standard D&D. In Confucianism, Taoism, and Buddhism, practitioners do not worship a single god or a pantheon, per se. For example, Confucianism does not worry about an afterlife, but the moral focus is on the here-and-now and cultivating the self to become a person of noble character.
Many psi-powers favor unarmed combat, and so having Psychic Warriors who are martial artists is no problem. I can see Egoists, Nomads, Savants, and Seers fitting right into an OA campaign. I'm not so sure that Telepaths or Shapers have any counterparts in Oriental mythology, but you can make them fit in.