[Edi]

Since the AI can't be modded directly, about the only way that it can be affected is by limiting its choices, which is the driving force behind both the Better Independents mod and the No Independents maps.

They work fairly well given the limitations, but fighting the AI is always dealing with hordes and fairly little magic (in light of the enormous potential that you see wielded in MP games). With the BI and NI solutions, you just face hordes of quality troops and more national troops instead of identical militia/light infantry hordes.

Something that would help if it were possible to set non-random AIs, ala creating an AI pretender with the point bonuses that could only be assigned to an AI nation (just like you can create and load pretenders for human controlled nations). Sure, you'd know what kind of build you're up against, but it would make for a better SP game experience when you don't have half the AIs turmoil/sloth/death/misfortune 3, which causes them to fall apart after around twenty turns.