[Valerius]

I guess you could split the difference between their original CBM and your modified cost and see how that works out. But I do think that the better troops such as storm demons and demon knights should be closer to your cost than CBM. I feel the same about commanders such as vampire lords and those annoying onaqui.

Tackling the issue from a different angle, you could also reduce Demon Cleansing to Ench. 8 or even 7. This wouldn't interfere with the first half of the game when the opportunity cost of blood hunting/summoning is felt most but would kick in during the mid-late game when blood nations can really start summoning large numbers of demons.