There are just a few things wrong with your post. First of all, Garchomp sits at an amazing speed tier, allowing it to outspeed up to Landorus. It also outspeeds Genesect, Dragonite, and Haxorus. In fact, it is the fastest Dragon-type with the exception of the Lati twins. Garchomp has one of the highest Attack stats in the game, and Haxorus's slightly higher Attack doesn't matter when it gets outsped and KOed by Genesect. Sand Veil is just another reason why Garchomp is so dangerous. In response to your point about not having Dragon Dance, Garchomp doesn't necessarily need it, especially because if it did, it would be extremely broken. Garchomp already has Swords Dance, and that makes it extremely powerful. In addition, Garchomp is probably the most bulky Dragon after Multiscale Dragonite, it can definitely take a hit or two, and even random Ice attacks if you give it Yache Berry.
Garchomp was banned in OU for a reason, but in DW the metagame is balanced with its presence.