to appreciate the talent involved in a good whack shack-a-lack backside hack 1) try one. 2) watch the slow-mo and see for yourself how they nail it. guys like medina and young (imh0) deserve to be scored well.
I think Gab's and Nat's backhand whacks in and of themselves are absolutely sick, but one of the scoring requirements is a variety in your maneuvers. I'm speaking more to the do the same turn 3 times and get a 7.5 thing that seems to happen with surfers on their backhand.