I find the AI to be quirky.

Most of the time it's unable to do anything much, then in other battles, it really does do well, flanks, has troops hidden in forests, managed to defend well...

Last battle last night was one of those "Oh, shit!" battles. I had a weak right because I placed all my cannons there, were tired and wanted to go to bed. The AI ran around a forest with 4 cavs and took the cannons out, retreated because I weren't fast enough, then it came on with line men on the right and charged back with the cav.. And through the forest on my right side came 3 units of pikemen marching in tight formation...

SMUSH! I lost 1200 men.. :P

It will probarly pay for that today though, but, for some reason, I guess the AI mainly gets stuck in loops somehow, but when it does work, it's actually pretty damn fun.