>>18504096Gained a new x4 weakness and has a type that is immune to one of its STABs and resistant to another. Similarly to how Salamence was all about spamming outrage Hydreigon was all about spamming Draco Meteor. Salamence is UU as well in case you haven't been keeping up.
Steel losing resistance to dark gave it a solid second STAB to fall back on but it just so happens that the same type immune to Draco Meteor also resists Dark Pulse.
And then when you consider it needs Superpower for Chansey and Blissey, you realize that 3 out of its 4 moveslots are walled by a fairy type.