So simple yet so hard (or even impossible) to see in Hoi2.This comes into its own with the invasion system. An invasion is no longer just simply shipping some units into an enemy province. It is a combined arms operation; it involves land units for the landing. Transports to move them. Naval units to escort the transports. Battleships to shore bombard the beaches. Air units to provide air cover and bomb enemies.
I want to see this in action.