In Heroes of Might and Magic III, I had many instances where, out of the entire army, only level 7 units remained: archdevils, titans, and I could easily defeat the entire enemy army! For example, once I had 10 titans left, and the enemy had a Swamp faction with levels 1-6: 9 vipers, 15 mighty gorgons, 30 great basilisks... And I easily defeated the enemy army, losing only one titan.
In Heroes of Might and Magic V, I haven't been able to do anything similar yet...