I've been thinking about how to make warmonger more interesting/less objectionable, without doing away with it all together. My idea:
- The warmonger penalty has a per era 'cap' (your total can never get above), that's that amount that fade in about 2 eras. So even if you went full surprise war and wipe out civs in the medieval era, and then went peaceful, you'd get back to 0 in the industrial era (which seems about right).
- Your warmongering penalty is reduced by your opponent's warmongering penalty (by the ratio with the above cap). So if the medieval era cap is 50, and you declare war on the Aztecs, who already have a 25 warmonger penalty, your warmonger penalty is reduced by like 50% (though there probably should be some cap below a 100% reduction). This means you can go after other warmongers easier, and also means the AI will go after the player more aggressively if they are waging war (as there is less penalty to do so).
- I think there should also be separate AI penalties for 'attacked declared friend' and a positive for 'attacked someone I denounced'.