This is a very interesting topic not just for TaeKwonDo but since TKD is what I primarily do I will post it here. Just to take an example outside of it: Freddy Roach, the famous Boxing coach, had a heavy bag clip up with a pretty famous fighter hitting the bag. It looked solid to my minds eye, yet some coaches commentating on youtube felt it was terrible, others polar opposite. It's pretty amazing how opinions can divide as much as bad or good over an elite competitor, it's not even a disagreement in spectrum... So basically, is there any objectivity in martial arts? I'm starting to feel that there really isn't.