Easy to counteract by defining tasks at the level of Theater and Army Group AIs. Let's say you have a Theater-level AI on the Eastern Front, commanding an Army Group with 2 armies in it.
Theater AI - attack the Soviets once the spring mud dries up; Army Group X advance towards Baku
Army Group AI - assess Soviet strength along the front; Army 1 and Army 2 form the two prongs to encircle the largest concentration of Soviet troops known to exist on the way to Baku; issue orders for two armies to advance to provinces Z and Y (determined by the combination of shortest distance and weakest resistance on the way)
Armies 1 and 2 - assess Soviet strength along the army's sector of the front; rinse and repeat Army Group-level tasks at the Army level (Corps I, II, III given their target provinces)
Subordinate Corps - rinse and repeat with Divisions
That's the conceptual outline of how it works. This iterative planning process is COMPLETELY impossible to implement with HOI2's monolithic "fronts." You can't break down the tasks into trivial components, like "attack province Z."