The problem if you make the cooldown shorter is you will need to swap weapons much more thus losing more dps. When it was insta crits this made sense, not sure it does now. Maybe a better idea would be either lower the stun dc's so you have less of a chance of 'wasting' a weapon swap or slightly increase the stun duration.
Now, I only find it useful on casters as taking them out of a fight for even a short time can be useful.