The thing is that there is already a rule that covers this very situation. It's called spearing. It is SUPPOSED to be called when the player initiates contact with the TOP of his helmet. Unfortunately, the best recent example of this was Shazier's hit when he got injured. But I defy you to recall a time this penalty has been called this century. But it was regularly called back when I played in the 60's, and by the time I was coaching in the 70's and 80's, it wasn't called very often because coaches back made it unacceptable to hit with the top of your head. I would sit a kid down if I saw it on the field flag or no flag. It was simply unacceptable.
However, I will make this distinction. It WAS acceptable to hit a player with the FRONT of your helmet (the forehead and facemask area). In fact, the ideal was to put your face(mask) into the chest of the ball carrier and slide to the shoulder, lift and look UP.
Now I'm not sure if this "ideal" would be acceptable now. Getting to see someone actually wrapping up a ball carrier is now a rare occurrence on Sundays. Now they just throw their bodies at the runner and hope for the best. Most of the time they have their eyes down, which results in missed tackles and more injuries.
The Pats are better at tackling than most teams but still, I cringe every Sunday at the poor tackling I see at what's supposedly the highest level of the game.