I think it would be worth replacing either Dungeon (it won't participate in the campaign in any way) or Necropolis (the same, and the ability to use their mandatory skill "Necromancy" to replace it with the "Blacksmith" skill - allowing you to create artifacts from Forged Ice for action points (and experience?)
Mugaiz, write down the units I suggested. I see there's more activity here, let's see what people say.