One thing I always wanted in Civ 5 and now would like in Civ 6, would be the ability to create a custom difficulty level for the AI. One thing that always frustrated me in Civ 5 was that some of their bonuses would out pace my own personal abilities. For example most of my games in civ 5 at king level or greater, I would usualy outpace the AI in techs by the late stage of the game. But if I chose i to high of a level then they starting getting bonuses in other areas which make it less fun for me to play. So somesort of menu which would allow you to decide what areas of the game the AI would get bonuses would be nice.