Could it be cool to assign missions and quests to other Civs, kind of like Sins of a Solar Empire Does? For example, missions to kill military units, capture cities, pillage tiles, capture civilians etc. (If you can think of more civil quests, those could be fun too) Edit: perform spy missions in specific cities. I'm thinking for games against the AI. A historical example: During the Crimean War, the British and the French teamed up against the Russians to prevent them having a Southern Port. This mechanism could allow you to coordinate military strategy with the AI, and allow other Civs to coordinate with you. Or at least, just get an idea of what other civs consider strategically important. Give more personality to the AIs.