Simple as. I know that ARR classes can't be removed from old gear due to the concept that players who would possibly return to the game without their job stone breaking things, but you can remove ARR classes on all future gear so we don't get players in duties level 91 and up showing without their job stone.

Do not put PGL, GLA, MRD, LNC, ROG, ARC, THM, ACN, or CNJ on ANY of the new gear. Item level requirements will take care of the rest and this will, by proxy, require a job stone for duties.