Recently the diplomacy logic of the AI has been changed to more heavily factor in proximity: Being nice to a neighbor is much more impactful than being nice to someone at the other end of the map. I think the same logic regarding proximity should be applied to City States. More specifically, I think being close to a City State should give you an advantage when it comes to how your military power is evaluated and how much influence you gain with diplomatic Units and Quests. This would make control over City States more of a local conflict rather than a global one ("sphere of influence"). The reason why I'm proposing this is because I think it would make conflicts with your neighbors more interesting. Also, I think it would make City State Diplomacy more even across difficulty levels. On Immortal and Deity I think it is very hard to keep even one or two City States loyal against the AI because they can pump out so many diplomatic Units. I oftentimes find that the AI contesting my allied City States are not even that close to it. Because it's so expensive (in terms of production) to keep City States loyal I almost always just kill nearby City States to avoid the risk of them flipping on me. In addition to that on higher difficulty levels you currently almost never get to demand tribute from City States because some AI on the other end of the map has more Units than you. I think that this is a poor judgement of which player is an actual threat to the City State since even a weak player can kill a City State if they are close. Implications of my proposed changes: If proximity is factored into City State diplomacy it would make tall Diplomatic Victories more difficult. (I don't know how good or bad this strategy is at the moment).