or you can do what I do and just use AI mods and keep the game vanilla.
DarthMod
ReallyBadAI
XAI
I favour condottiere's CAI purely out of personal preference. Can't find the link to the page where I got it from tho so no feature list. Germanicus' ReallyBadAI has got an aggressive battle AI but you're gonna have to pull the files manually to mod med2 as it's really meant for kingdoms mods.
There's also UAI for Med2 but can't comment since I've only ran it for a couple of campaigns.
They only change campaign and battle AI files so your game is still vanilla. In case if you haven't done it before, you'll need to read Achilla's
instructions.