Strongest class/job lore wise?

[Velox]

WHM and BLM are dangerous in that, through practice of their arts, they are borrowing aether from the planet to cast their spells. Using too much aether bleeds the land dry and leads to calamities. Primals feed off the land's Aether supply as well to exist, and we have to put them down because if the same risk. This is why the use of White and Black magic was deemed forbidden, it destroyed the entire world once.

In essence, every WHM and BLM is a mini-primal, sucking aether from the environment to make their flashy, lag-inducing spells.

[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.

[WyrahFhurrst]

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.

What do you mean they haven't made Summoner's origins clear yet? They're Allagan in origin, brought back by Sharlayan scholars who want to see it flourish again. None too complicated and explained in their storyline.

But on the topic of who's strongest, Summoners. They literally wield the power of Primals, and can now call upon the power of Bahamut and his strongest attack Akh Morn (Deathflare).

[zuzu-bq]

I was not talking about from where they come from, but about the original Summoners' power.
About Deathflare: that is something you, the Warrior of Light, can do. We don't know about what the Allagan Summoners used to do and the Summoners' job quests always happen like "wow you concetrated so much that you can do this random new spell now".