I'd totally be down for this. It would add for greater character customization without relying on stat points or leveling a ton of different jobs to do so.

It could also fix the equipment issues, people equipping gear way out of their rank range, etc, without imposing a level requirement on gear. Want to wear that Hauby as a Rank 12 Gladiator? Fine, but make sure you have your Haubergeon gear license.