Some non-European, non native (North) American civs that I would love to see:
Afganistan: Turtle civ with bonuses to trade routes as it was a crucial player in the silk route, has always been a centerpiece in geopolitics.
Khmer: Tall oriented civ with UI (baray) and insane bonuses to their capital, which was the biggest urban center of the world for centuries
Ashanti: One of the biggest African empires ever, they could recieve bonuses for fighting with gunpowder and religious integration / tolerance, since they were one heavily multicultural civ
Mapuche: Want a native civilization far more deserving to appear than either the Pueblo or Sioux? Try these baddasses, only native civ able to stand agains the Spanish