I've been playing Imperator with Chaotic AI turn on as Carthage. I've reached a point where I don't know what I'm doing anymore. I conquered all of Italy, most of Iberia, half of Egypt, all of North Africa, Judea, and the Sinai, and I'm integrating a tribe that owns 3/4 of Gaul and all of England and Wales. I have about ten accepted cultures, which might be too many, but research is going well, and I accepted them to gain their unique techs. The Macedonians are my biggest present enemy and are blocking me from completing my mission tree because they hold Greece and Anatolia, but I only have 150 years before the C3C starts. I'm considering decentralizing my empire after I break the Macedonians.
Here are a few things I've learned from this run:
The mod "Realistic Tribes" is completely useless if you plan on making tribal vassals. It causes their national civilization to tick down every month, which would force them to migrate if they ever actually moved their capitals. Instead, I had to cheat a few times because they would practically never consider, and especially not finish, reforming.
You should watch out for the mod "Paler Romans". It completely fucks up the history files. Characters are shuffled everywhere. I learned that the hard way on some failed runs.
If you're playing with Border Cleaner, lower z_border_cleaner_manual_size_threshold in z_border_cleaner_values.txt to 1.
Add always = no under is_party_type = democratic_party in senate_objectives_generic.txt, senate_objectives_roman.txt, and senate_objectives_car.txt. Realistically, the democrats wouldn't push for expanded citizenship in almost any nation, and citizenship in IR doesn't do what it did historically.
Playing as a republic is more stable than playing as a monarchy.
If you don't plan on integrating the majority culture of a city with a capture event, or don't plan on releasing a nation which will own that city anytime soon, just destroy the city. There are typically plenty of other cities in the area.