Breaking Swipe is not a powerful STAB. There's literally no reason for using it at all over Dragon Claw, Dual Chop, or Outrage. Iron Tail is much worse than Iron Head, Superpower, Earthquake, and Fire Punch. Brutal Swing is a really random and overall terrible choice, Giga Impact is an atrocious move that gives the opponent a free turn to set up, switch, or KO you, and worsens your overall matchup vs steel types. Also that is a very bad EV spread for an offensive Dragonite. Why run Leftovers and Impish over Weakness Policy/Heavy-Duty Boots and Jolly, and why run Agility over Dragon Dance?