Hydreigon can be played in many ways, but I would like to focus on the Choice Spec set. It has the potential to wall break through pretty much anything and that’s not necessarily a bad thing; there are several locked mons that are impossible to counter or wall completely and that’s entirely fine. My issue with Choice Spec Hydreigon is that, unlike other Choice Spec or Choice Band users, there is almost no prediction risk involved.
When Roserade locks itself on Sludge Bomb, there is a risk that offensive answers like Escavalier or Klinklang come in play and punish the locked mon for free. When Krookodile locks itself on Crunch, there is a risk that offensive answers like Durant, Scrafty or Bisharp come in play and punish the locked mon for free. When Darmanitan locks itself on Flareblitz, there is a risk that offensive answers like Chandelure or Salamence come in play and punish the locked mon for free. When Hydreigon locks itself on Draco Meteor, no offensive answer can come in play and punish the locked Hydreigon. Assuming you know your opponent will do Draco Meteor on Spec Hydreigon, you still can’t send your offensive dragon resistance against it since they are all outsped by Hydreigon and get 2HKO:
That’s a huge problem since it implies that, whenever Choice Spec Hydreigon comes in play, it gets a kill on anything that isn’t a wall; there is no way around, no offensive mon can handle a Spec Draco Meteor in the face.
If Hydreigon was a glass canon, I guess its wall breaking capacity would not be a big deal, but Hydreigon got a very good defensive typing, ability and very bulk. Unlike Yanmega or Porygon-Z, Hydreigon can come in play with relative ease.
Some may argue that being locked on Draco Meteor when killing a pokemon comes at the cost of the opponent being able to set up on you. However, in order to make losing a pokemon worth it, the opponent needs to be able to set up an incredible sweeper that in normal battle conditions would not be able to set up. Set up sweepers like Scizor, Gyarados, Togekiss, Volcarona and others can still be countered in the exact same way they always get stopped, so those hardly take advantage of Hydreigon being locked. Cloyster and Sniper Kingdra are on the other hand very destructive as sweepers and are much harder to set up usually. Sadly, they still can’t set up in front of a locked Hydreigon. I guess Lucario is pretty good at revenge killing Hydreigon and setting up on it, but sadly I don’t consider Lucario as a very competent sweeper in our metagame. I guess it’s a matter of opinion when it comes to Lucario, but overall, even if Lucario can take advantage of locked Hydreigon that’s still not a big tradeoff compared to what Hydreigon has already accomplished imo.
Let’s now look at the walls that can come into Spec Draco Meteor Hydreigon: Blobs, Milotic and Ferrothorn. Ferrothorn comes in at the risk of getting OHKO by Flamethrower from the Choice Spec set while the blobs take the risk of coming into a Superpower set.
I also would like to add that unlike Kingdra, when Hydreigon is locked on Draco Meteor, it doesn’t fear being revenge killed by Pursuit Scizor.
So overall, even though Hydreigon can be played in very different ways, I believe Hydreigon with its Choice Spec set already fits offensive uber characteristics and should therefore be banned.