Idea: Add kind of personalities to countries / rulers and personalities to them. For expample, agressive country: attacks others a lot, has an attack buff, but revolt chance grows faster and drops slower. Or for example diplomatic: is rarely attacked by enemies, and attacks only when they are definetely weaker, also easily make peace and alliances, but they have a weaker army. Or a peacekeeper one: If able to help, helps an invaded country by attacing the invader. Also relations will be nice; it seems unlogical seeing countries who have been allies/in peace for a long time waging war on eachother.