Something to punish block spam.

As I play the berserk class, when I go up against a grunt they tend to block spam and I can't find a work around unless I have a speed potion on me. They can block daggers, melee attacks, and even the berserk whirlwind. I know that the crush can break block, but it's too slow and doesn't move my character towards them that much. I think blocking should be something that's useful if you time it correctly instead of spamming.