Strongest class/job lore wise?

[shinros]

Well its pretty obvious the big three are BLM, WHM and Summoner yet those jobs dangerous to use as well, there is a cost just like DRK, WAR and Dragoon for their power.

[Waffilicious]

yes it is suspected the 3rd was allagan fall and war of magi was 5th umbral

[Zohar_Lahar]

Allag ended with the Fourth Umbral Era. The War of the Magi triggered the Sixth Umbral Era.