I have a few practical issues with the a-d criteria. I understand them in an ideal situation, but many defensive situations aren't ideal in that both parties are moving (even after the defensive player makes his move).
Using the Ellis Brooks play
Per A, Brooks did not lower his head
Per B, there was not a lot of evidence of form tackling, but back to the situational nature of football, and the choice between form tackling a 220+ lb QB 2 yards short of a first down, and forcing him out of bounds with what was pretty much a chest/shoulder push, the latter makes more football sense to me. So all Brooks needed to do was put in hands up and around the QB as he continued to push him out of bounds was enough..seems a little too much style over substance for me.
Per C, Brooks had both feet on the ground for some time before the contact. It's hard for me to label the play as 'launching'.
Per D, yes there was post-initial contact and not with the crown of either player's helmet.. Given momentum, I think this criteria needs adjustment. Again applying physics-isn't that the science of force?, the angle of impact should be considered. The worst case scenario is a crown-to-crown where both players have their heads down. In this case, Brooks' helmet rode up the side of the QBs helmet. I don't think the helmet to helmet/or even neck contact was the majority of the contact or force, and especially questionably 'forecable' contact at that.
So of the 4, Brooks' situation had between met between 1-maybe 2 of 4. Can unquestionably meeting less than half the criteria justify this call?
I understand the desire to foster pure tackling and contact techniques that prevent unnecessary injury, but I feel getting there in one step with rules that allow broad interpretation isn't the right way.