If would be more realistic if more weapons had the crushthrough ability to be honest. However, it could be less chance for it happening than it is now. Also, hits that crush through a block should deal a lot less damage than an unblocked hit, and should not be able to knock people down. What I think most people hate about the crushthough is that it deals the same damage whether you block an overhead swing or not, and you most likely get knocked to the ground making you most likely die on the hit the enemy gets on you while knocked down.
I'm not really sure if it is possible, but perhaps "nerf" the crushthough ability a bit by making it deal a lot less damage through a block than when unblocked. Also possibly giving more weapons back their crushthough ability, but with a lot smaller chance for it happening based on the weapons weight and the users strength.