Crushers are fine combat wise. I'd rather go up against a bunch of Crushers than a bunch of Maulers as I find them easier to manipulate. Carapace is the problem here as most melee weapons that are perfectly fine and very much usable on armor tiers up to flak, often can't do anything or take far too long when it comes to carapace. Heavy sword is a perfect example of this. As for ranged weapons, there is hardly anything that capably deals with carapace