First of all I want to say this is a brilliant mod. However the AI seems a bit out of whack. They sometimes wander around the front of my army when attacking, always shying away from a frontal assault while I bombard them with the now absolutely lethal arrows. Other times, while fording a river, they will mill around indecisively on the far bank or come over in complete disorder before running around randomly on the other side of the bank without attacking. Combined with the positively fragile morale (or maybe I'm just used to Medieval II's habit of having peasants fight to the last man) this makes picking their units off with well placed cavalry charges very easy.
...of course as I found out fighting one of the historical battles (I had to rescue a king on a hill and got slaughtered by helmeted nightmares) the AI is also capable of surprising brutality.
Essentially the AI isn't hopeless, but it is a bit wacky and unpredictable. Has it been changed from BI's standard format or have I just forgotten what Rome is like?