Tore, your way of boosting the Ai is fairly limited. Since most factions bleed money every turn the 400,000Mnai boost you gave would only last for a few turns before it disappears and the standard script would kick in.

Your best option to boost the AI is to give them massive law bonuses to their core buildings (give it too all factions but yours) and then increase the movement of all campaign units by about 50-100%. Standard movement is 80 but I like to use about 140 or 150. This will allow the AI factions to make serious raids into neighbouring territories and stop them from being so passive.

The downside of this is that it favours super-factions more than minors. Rome and Carthage and lusotannia will dominate the west while the Arche Seleukeia WILL dominate the east and eventually the whole world. Still, you may find it the challenge you like if you leave the AS alone for about 20 or 30 years and build your own western roman empire first.

Good luck.