>>22791986Ran some calcs
252 Atk Landorus-T Earthquake vs. 252 HP / 252+ Def Reshiram: 254-302 (62.8 - 74.7%) -- guaranteed 2HKO after Leftovers recovery
+1 252+ Atk Tough Claws Mega Charizard X Dragon Claw vs. 252 HP / 252+ Def Reshiram: 410-486 (101.4 - 120.2%) -- guaranteed OHKO
4 Atk Mega Diancie Diamond Storm vs. 252 HP / 252+ Def Reshiram: 236-278 (58.4 - 68.8%) -- guaranteed 2HKO after Leftovers recovery
252 SpA Choice Specs Latios Draco Meteor vs. 252 HP / 252+ SpD Reshiram: 404-476 (100 - 117.8%) -- guaranteed OHKO
Even with the bulky sets a majority of the meta still handles it well.