What they really need to do, is level cap classes at 30. Force players to get/equip their job crystal to advance further. It would be a permanent level sync without the crystal equipped. Cannot gain experience and can't queue up in duty finder for anything higher level than 30. They can toss all the level 34 cross class abilities to level 28, (put mantra at 24) and really drive home that classes are the "newbie school" of battle.

Speaking of newbie school, they need to make the hall of the novice mandatory. Put it as a part of the MSQ for new characters. As for veteran characters, they must complete it on a given role before they can queue up in duty finder as that given role.