i think if you give them the spot where butt hits ground then you HAVE TO allow a defender to hit him up until that point.
you just cant tell defenders that they are helpless the second they start the process and you cant touch them at the same time giving them the spot where they hit. that just doesnt make sense.
then you have defenders teeing off on a qb who's in mid slide. which would be great from an entertainment perspective but again, you'd have dudes going off on stretchers every week.
Can I ask you a question? What is the difference between a regular ball carrier being tackled and a sliding QB being hit? The rule was the way it was for 100 years and there were no serious injuries that I can remember. A sliding QB has an opportunity to protect himself during the slide and if he is that afraid of getting it, just fall over and dont slide.