Strongest class/job lore wise?

[zuzu-bq]

Even tough Black Mages are the embodiment of destruction themselves, I would say White mages since they had enough power to create the Calamity that brought Eorzea into the Sixth Umbral era.

It's hard to say something about Summoner, since the game still haven't made clear what are its origins yet and how a full power Summoner should be.