Noticed a new bug/oversight now that ammo-less troop reassignment works: the ammo-less division defaults to "charge" which leads to dead troops unless you're paying close attention. Ideally, you should be able to assign an order in the planning stage even if you don't have troops in that particular division, or make the ammo-less group inherit orders (ex: first re-assigned troop sets his original order, at least as far as "hold" goes; "skirmish" could be transformed to "retreat", etc). EDIT: this is, of course, only valid if the ammo-less division was empty before the battle started. Likely applies to all temporary divisions formed during a battle.
Also, I'm not sure if this is a bug or incomplete feature: I've never seen the "Formations AI" take over for my side after I've been knocked out - my troops just carry on with their orders.