After playing the mod for a bit, it's come to my "understanding", that you should add an option to remove formations.
First a gameplay reason: Cavalry has almost completely lost its advantage now, battling Nord armies is hell- as far as I've noticed.
But (and this may belong in the bug-thread) there also seems to be a mechanical problem with the way formations act. There were several occasions where I just didn't understand what the AI was doing, like once after an Agonic horse-charge killed off the enemy's first way, they just stood around in a blob where they had faught earlier while the enemy circulated around them and eventually just stood still... I wish I could describe this problem more in order to help the progression of the mod, but that's pretty much as good as I can put it. And if I'm not mistaken it's likely mostly due to the formations-thing, but I'm not a modder so I could be wrong.