You folks should really stop declaring anything as the next type to dominate or the next Pokemon to rule any rule set. Dragon had a lot contributing to its ridiculousness. The good neutral offensive typing was just a contributing factor. The good defensive typing with resistances to Water, Fire, Grass, and Electric, high BST users, and ridiculous base power attacks like Draco Meteor and Outrage made everything too good. I've seen a lot of people parade Gengar and ghost types as the next big threat, but they really only fulfill the good neutral offesive typing part. Ghost's immunities still leave it taking neutral damage from a ton of common types. Ghosts also have comparatively low base stats and have a mighty base 80 attack as their strongest stab. If anything, I see ghost becoming more akin to the Electric-type than this games Dragon-type.
We also are still completely in the dark for what new moves and tweaks to old moves gamefreak has in store. For those proclaiming that Scizor looks set to dominate, for all we know, Bullet Punch could be nerfed to 30 Base Power or we could get some held item that prevents moves of increased priority from working.
To put it simply, everyone's excited for the changes and thinks certain Pokemon are seeing big buffs, but calling anything useless, overpowered, or bannable at this stage is really dumb.