I'm not sure to what extent the AI types affect the different factions, apart from what they build and train. For example the Byzantine are 'orthodox_stagnant' which would lead one to believe that they are a passive faction that does not do much to improve it's ecomony orstanding in the world, yet experience tells us otherwise. The English are down as 'catholic_crusader_trader' (from memory, apologies for any errors) yet I've found that they crusade less than the HRE, the French and the Spanish. They also trade poorly to start with. This may be down to (bad)luck. The English are thrown into conflict with the French from day one, so they may not have much opportunity for trading and crusading. The only AI that really makes much difference is the 'barbarian_raider' (Mongols). They don't seem to build alot, which is why I think the AI types are limited to building and trading, and nothing else. One could say that the KGH are much more aggressive, though that can be attributed to them emerging into one or two provinces with a massive force. Any AI faction would be highly aggressive under those circumstances, as it's been proven that the AI attacks alot if it has alot of units at it's disposal, and it's stacks outnumber the enemy's across the border by a large proportion.