Belichick has been using a tackling technique for several seasons that is a good work around with the CBA limitations on tackling in practice. The tackler must pick up the ball carrier and the only way that is feasible is with the shoulder so that not only protects the head area of the tackler but makes am better tackler.
BTW, since he installed this, his team leads the league in limiting yards after contact. Since when did lowering the helmet make a better tackler? Watch the best tacklers, see them lowering their helmet or keeping their head up so that can better wrap up. Lee is the best tackler on the team, watch him demonstrate textbook tackling, head up, arms wrapping up, ball carrier goes down.
I totally disagree with the premise this hurts the game. Tackling is a skill, a learned skill, ramming one's helmet into a ball carrier is not a skill and is also not effective tackling as the ball carrier can bounce off.
Now, here is a simple exercise to demonstrate the effectiveness of head up tackling, Approach your girlfriend or wife, preferably not both and certainly not at the same time. Put your head down in the ramming position and hug her. Feel awkward? Does she think you are awkward? Well, so do I. Now, put your put head up and attempt the same hug. Now, how was that? She may still think you are an awkward individual but a drop dead hugger.
BTW, you can get this little exercise and many many more in my new book "CouchCoach's Football Applications for the Bedroom". The chapter on "Under Center or the Shotgun?" is a real page turner.