the lack of magic among the Orcs is just a name...
The Fury of the Horde deals decent damage, sometimes over 1000 - an alternative to Chaos spells;
I don't see any difference between Punishing Strike and Battle Cry;
The effect of Terrifying Roar is similar to summoning a bee swarm, even better;
Warlord's Command and Unifying Cry affect the army's initiative in different ways, like a speed boost, but weaker...

Added 2 minutes later
So, everything is great for the Orcs in this regard, and you don't even need to learn the corresponding schools of magic...