Sure terrace farms are not a part of their UA, but you were writing about how the civs faired against each other which does relate to the reminder of the civ. In any case what I really like about the Incas as an OCC civ is that the population growth is so rapid that you can make up for the less science boosters and the UA makes them defensively very strong as you can move and shoot every turn. I don't really agree that they have less productions either, seem mostly like a choice to me. I think they have a mountain bias as well, I may be wrong, but observatory goes a long way in an OCC. They may not be better than Babylon and Korea, but I think they provide an easier OCC. And just for the sake of it: I did not vote based on anything but UA and my votes were actually for neither Inca nor Korea.