I'd agree, yes... but. Artifact Armour (AF) should be Job locked because.. that's it's whole purpose - it's that Job's uniform/identity so to speak, with appearence based on the original design/appearence of that Job in previous FF games - in a game where you generally wear generic gear it's the one time you can actually have your character look like that actual Job from past FF games, and thus it would lose that identity if tanks could freely wear WHM AF for instance.

But everything else I don't see a problem with unlocking.