I would probably guess BLM as they are avatars of pure destruction. None of the melees can really cause as widespread destruction as a BLM can. Melee jobs are probably powerful against multiple opponents, but BLM is a weapon of mass destruction. WHM too perhaps, as WHM was known to bring about an umbral era. A Dragoon could probably take out a knight,warrior,archer,rogue, given that they can leap from the skies and are extremely evasive lore-wise with their jumps and their spears can pierce dragon hides.