Lots of people here getting their panties in a bunch. Hip drop tackle is pretty obvious, almost as much as a horse collar. If a player has gotten past you and you're tackling from behind, horse collar/hip drop are quick ways to bring them down and minimize yards gained. They are both high probability of causing leg injuries, so I'm fine with them outlawed in favor of player safety. If you're caught in a trailing position, take your medicine, wrap up, and drive them to the ground while staying on your feet. If you have to give up a couple extra yards, that's on you for not getting in front of the player.