With the upcoming update, most, if not all currently obtainable moves/abilities/items are expected to function. This includes the implementation of Draco Meteor, and by extension, Draco Meteor on Hydreigon.   Due to the shift in Tiering Policy to avoid banning pokemon to Uber, and instead make ingame changes or tweaks, a proposition has been made to simply remove Draco Meteor from it's movepool before it is added, similar to the preemptive Outrage nerf. Although we strongly believe thi