In order to maintain game balance, powerful moves in pokemon were always designed in such a way that you have to accept some sort of trade-off in order to use them. Hyper Beam requires you to waste a turn to recharge, Eruption's power depends on your HP, Draco Meteor lowers your SpA, a lot of powerful moves have lower accuracy (Focus Blast, Thunder, Blizzard) and almost all of them have low PP. Dynamic Punch was designed to be a very powerful move that also induces confusion to the opponent, but it is only supposed to land 50% of the time. Anyone with some GSC experience should know the move is very lame even with 50% accuracy, let alone with 100% and I don't think we should have to deal with it. My preference would be to ban Dynamic Punch because I think the move is inherently uncompetitive, but I wouldn't be opposed to a Machamp ban either.