My biggest bugbear is infantry behavior under fire, especially in bocage terrain.
The hunt movement used to work so that if a hunting unit was fired on, it immediately dropped to the ground as long as it had a hide order. Now, they run in stupid directions (as in away from good cover and straight into enemy fire). They do this regardless of the troop quality.
Equally, when units are positioned behind bocage and move out of the bocage straight towards the enemy when fired on. If they are behind bocage, it would be better if they crawled away from it while keeping the bocage between them and the enemy, or crawled along the bocage, instead of making for the nearest gap at the trot and running through it right into the enemy fire.