Corps type size organizations has always tickled the back of my mind as a way to reduce AI division shifting on a front. Instead of 24 divisions swapping around with each other, maybe it could be only 3 or 4. The distance moved would be much less and and probably more logical.
After reading
@CrasherZZ's quote above, it occurred to me, Why would it be harder for the AI to use corps? As a matter of fact, even if the developers chose not to give the player corps, why not give the AI corps? The AI corps would not have to show on the map. The corps would not get a leader or any other benefits. Instead the AI could be told to always break down an army into groups of three or four divisions, or what works best, and then do what it always does, spread the army along the front, sorting corps first, then the divisions in each corps. This should greatly reduce the unit swapping as the divisions would only move around in their corps area.
I would not mind seeing players getting corps, or at least smaller armies, but maybe the AI needs corps to help fix its OCD in shuffling troops.