Why teach Orcs defense?
But it's actually very useful.
I think that, for example, a Cyclops under the Berserk spell will destroy a third fewer of its own troops if it has some defense. ;) Reflection is probably a good choice, then you can also take Barbarian Luck. I don't remember if they synergize or not.
Attack is a must.
It would be good to combine Machines with Fire Arrows. That's just devastating.
Leadership is essential. Definitely up to the speed aura. Battle Frenzy.
Logistics...
I still think that the most important thing is to get to the enemy troops faster. So, speed is needed.
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regarding the "dampeners."
This is a mage. It's difficult to guess which spell he will cast, Chaos, Light... I think it's nonsense to develop two "dampeners." It's hard to guess just one. Let's say, with the same Ogre... well, you can hope that she will choose Chaos, Summoning. Light is not so scary. So, you can take a Chaos dampener and magical defense, Barbarian Luck...
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And more Blood! :))