So, did absolutely no one attack when the hero approached the book?
This compensates for the lack of Might. And for Orcs, the lack of Might is actually a good thing.
I can’t say that Necromancers are devoid of Dark Magic. I specifically started playing as Necromancers for the “revival of darkness,” which is visible in the demos. The absence of “Berserk” and “Dominate” is not critical with such possibilities for replenishing the army. The main thing is that all mass spells are available.