I had played several campaigns and each and every time AI loses too much reputation, which causes a lot of unrest, rebellions and expenditures, and all in all ruins AI faction. It would be much more interesting if we had few really strong factions to give us real challenge in late game, but this ruins it completely.
So, here's what happens:
1. Factions sign some alliance pacts.
2. One faction declares war on another, then allies of the attacked country declare war to attacker, which causes allies of the attacker to declare war to all of the defenders allies, and this process continues to repeat, some factions even declare war on their own ally/allies because of entangled alliances.
3. Each country is now at war with several other countries, which causes their reputation to decrease fast.
4. Because of the effects of negative reputation, AI factions suffer (already mentioned unrest, rebellions and expenditures).
I don't have enough knowledge to fix this myself, so I would need some advice from someone (with some advice and explanation I think I could try myself). Here are some of the possible solutions to this problem (I think this will help, although I might be wrong):
1. Limit factions to only having 1 ally, not more
2. Make AI factions very eager to sign peace treaties when their reputation is too low. Maybe it would be better if AI factions only sign peace among themselves, not with player, because player could exploit their willingness to sign peace to gain more than he should. Also, make AI factions willing to sign at least one alliance so that their reputation could rise even when in peace (many factions never sign any alliances, but their reputation decreases as a consequence although they are at peace)
3. Limit reputation to -5 for AI controlled factions (or some other value, if it proves to be better)
4. Remove effects of negative reputation for AI countries completely
I believe that options No. 3 or 4 could be a lot easier to make, so I would prefer them
I apologize for trying to revive such an old and already finished game, but this is the only hot-seat multiplayer strategy game I know, and I still don't have a stable internet connection because of location of my house, so i prefer this game