A problem with Civ V is that one can always solve unhappiness by building more cities. That can't have been the intention, and of course, something should be done to counteract it. So far, most of the suggestions have been to punish infinite expansion, in various ways, and that's all right of course, but why not also introduce positive things that can only happen to smaller empires? For example, something like the Olympic Games in ancient Greece - an event that can happen fairly often in your civ, but only if it is rather small and homogeneous - that is to say, on the small side and without too many puppets or annexed cities (and the puppets and annexed cities wouldn't share the happiness anyway). Another possibility is to reintroduce religion; but the spontaneous spread of religion would be rather rare, especially on harder difficulty levels, and in order to spread the religion to all your cities, you'd have to build expensive missionaries who always would stand a chance of failing - also scaled to difficulty level. If a whole empire shares the same religion, that could be a constant source of happiness due to a feeling of community. (If some other religion is present in your realm, that should not matter one way or the other, except for it being harder to spread a religion to a city that already has another one.) The difficuty in spreading a religion should increase with each city that already has the religon, until it becomes virtually impossible to spread it further and get the happiness bonus. I want to make it clear that a shared religion should not affect the attitude of two civs to each other - religious sympathies were one of the major exploits in Civ IV, bordering on breaking the game. (And historically, countries sharing the same religion have often attacked each other, quite frequently in cahoots with countries with another religion. A Christian and a Muslim country against a Christian or Muslim country, and so on. In world diplomacy, material interests almost always take precedence to religious fellow feelings. In fact the First Crusade would never have taken place if a moronic Caliph hadn't stopped trading luxuries to the Europeans, and furthermore, if there hadn't been a lot of landless European younger sons of noblemen itching for an estate of their own.) On the negatiove side, why not reintroduce an old mechanism from Civ II? In a slightly different form. If your empire is very large, there would be a definite risk that it will spontaneously split into two different empires, and you're only master of one half. That could be really cool. (Especially if you see Napoleon or some other warlord stopped in his tracks by it, but it should be quite possible to happen to YOU. Naturally, the expansionist should have some ways to try to counteract this happening, but make it hard for him! Eh? Because that's what the expansionsists say they want - a harder time.