I am against power leveling for the same reasons mentioned here. I see too many players who are poorly trained and do not add anything to players game experience. Imagine a poorly trained bear and you and some others are killing a boss when along comes a bear and stomps the boss out of the room so it heals itself. I am not picking on bears but I have seen too many stomping bears change the complexity of the game. Players power leveled have not taken time to learn their character and in many ways are considered undesirable players you would want to run with.