Make it so other AI controld civilizations spawn in the head capitals of the country’s on the map. And have them fight eatch other and you just not in the begging so you have time to start of. And also not to often so you have a sense of relaxation. Also have it so you can switch enemy’s on and off. And have a relationship system.
Are you thinking a clear line between war and peace, and that there is just something in the UI with other tribes that says ‘at war’ or ‘at peace’, or do you mean there being a relationship system with higher chances of attacks the less they like you, and vice versa?
Depending on relations. A bit like civilizations relations system
A civilization-esque war system would be neat to see in a game like this. Although, just a simple “at war” or “at peace” (like Duck had mentioned) would complement the simplicity of the game and fit well with the style.