I can't see Garchomp outclassing Haxorus, especially now with his new moves introduced in BW2. Haxorus still hits hard like a truck and he has Dragon Dance, something that Garchomp dreams with. The Double Dancer Haxorus set is something that Garchomp won't be able to pull off, neither in power or speed. Maybe now Haxorus will be worse as a scarfer, but there were few who used it with Scarf anyways. And Haxorus is still able to hit Rotom-W, Gengar and Bronzong for super-effective damage, something Garchomp can't get.