I'm surprised that no one has emphasized the fact that given a long enough map distance every AI army eventually morphs into a giant ball of out of formation units. The only really interesting battles are when you deploy in a line in the middle of the deployment screen and move towards the AI and a few rare cases where the BAI works right. Barring very few case, most battles devolve into you sitting there in a nice formed up line and the AI army twice as large with their formation turning into a giant clump as they close....