The leading with a helmet penalty is bogus. I cannot count the number of times I saw a RB lower his head and run into a defensive player this last weekend and it was never called. It is only in place to aid the offense in scoring more which in the minds of the NFL (and fans) equates to a more exciting game and ticket sales.
Same way with hands to the face. When is the last time you saw the refs call a penalty to a running back or reciever for stiff arming a defender with their hand on their facemask.