This mod seeks to make the CAI function better and as a result I've changed some campaign functions to reach this goal. Eventually I'd like to have a game that looks like a pyramid with a few large factions owning most of the territory at the end. That might not be possible but I'll try!
Stuff that has been changed:
Factions will now take desolate settlements much more quickly. While i haven't done anything with the CAI's occupation decisions this makes it so that the map isn't covered in wasteland the entire time as you will see in the screenshots below.
The cost to resettle has been reduced.
Great power modifier has been reduced and caps at -30. I might increase this a tad to -45 in the future. It is a good balance between keeping allies without struggling to do so, but at the same time, creating conflict where needed around the map. I haven't modified the rate at which imperium is earned, just the penalty from it.
The CAI should be less willing to go crazy distances out of its way to attack the player.
Corruption has also been reduced, the Roman factions should be a bit more evenly matched instead of crumbling right away. However this might make playing as the romans much easier but i haven't tried yet.
The CAI should be more intensive locally both in diplomacy and military.
Fertility should cap at half or -2 I think of the max. This will keep regions still viable instead of plunging the entire map into a worthless state.
I will continue to update and tweak this. Right now i haven't cleaned up the mod files but it will probably not be compatible with anything that modifies the CAI or anything else i talked about above anyway. Let me know how it goes if you try it out. Thanks. 
Screenies. If you want the color mod i used in these screens you can find it here. It only changes the color on the campaign map to help distinguish between factions better.
Turn 18
Turn 30
Turn 40
Turn 50