Using rare items like those in quests would be a solid way to go, much like how you need a Brown Belt for the Black Belt.

Perhaps this thread would be more appropriate for your suggestion:

Quote Originally Posted by Ophannus View Post
MNK have Belt quests, mages have spell quests, SMN has Evoker Ring quest, NIN has scroll quests. Can you introduce more quests for more jobs that reward them with JOB SPECIFIC equipment?