I don't think GM gear players never see will preclude any jobs from happening. Back when gunblade was announced as the next job weapon, speculation was that we'd get a Garlean mentor or magitek knight job to explain why that is, but they just wholly invented a new race and ancient history of the gunblade that it turns out Garleans stole as to why we have a the Gunbreaker job, so they could easily do the same thing saying that Judges were an ancient order from Landis that Garlemald appropriated when they conquered them.