>>96362129
I think a simple 1 per army would prevent them from overrunning things. Personally, in my games, I've never had any trouble with Dreads appearing on the table, it's just another aspect to play around tactically or to intentionally target for the points it awards you. Hell, merely disabling it nets you half its points as reward.
Again these are just my thoughts and how we play the game locally, but I think it's worth considering.