3 of these Civs make an argument for the best civ overall.
Babylon, Korea, and the Inca.
Bab and Korea because how powerful science is in game. Inca because the hill movement allows for movement in warfare that the AI can't handle and powerful in multi. The tile saving/road saving costs make a large empire super cheap to maintain and you run huge gold surpluses in the early game. Add it to something like Tithe (haven't tried Inca in GK) and games where I was getting 300-400 gold per turn at 1400 a.d. (pre-tithe) would just be insane.
Plus Terrace Farms are pretty good - (Try getting these with Petra, not uncommon since Desert is one of the possible biases for the Inca)