A question springs to my mind
My guess is (without really knowing anything about AI): we get whatever AI gains exist in the FFH/FF version that we build the mod on top of, but it will be hard to integrate whatever they add later.
I wonder how the AI will react to the absence/presence of some units in various OBs
Well, most basic unit functions are still present in most sides. The AI can use a chariot and a shock cavalry the same way, and if they dont' have a knight they can still generally build a lancer.
I suppose we could have problems, but this didn't seem like a big worry to me, at least initially.
I'm really afraid it will be totally cakewalk to kick AIs asses, militarily speaking
What is it that you are worried about?
If anything, I think it will be harder to beat on the AI relative to the old WH mod, because more of the RockPaperScissors system advantages the defender, so it will be harder for the human player to conquer the AI.
Plus, changing the bombardment system so that catapults aren't as uber will help too.
but it would be good to have a clever advice from someone which has done so.
Cephalo seems to be the AI expert these days.
But my understanding was that there were a handful of unit AI roles, and we still basically stick to those:
City defender (bowmen)
Stack defender (spearmen, crossbow)
Explorer (recon)
City attacker (sword/axe)
Siege (catapult/cannon)
Mobile/mounted (chariot, mounted)
The AI basically has some city defenders, and then puts the rest of its army into a big super-stack and invades, bombs the walls, then throws everything at the enemy.