My idea of adjusting Crushers as enemy due to their armor that limits weapons usage, etc. Is that they are missing a piece of armor that creates a non-weakspot unarmored area, think missing shoulder pauldron, having a hole in chest armor.
Additionally, I think it would be cool if you add a certain amount of brittleness or you throw krak on Crusher, he would remove his chest armor and throw it at the player charging in as an enraged mini boss (Think Mr. X from RE2 when his coat is removed and he mutates into Super Tyrant)
Both cases would increase weapon viability
and change a boring enemy into a more interesting one with a cool mechanic.