Wondering how long before someone sincerely suggests that it should only be an unlimited job.

That said, with certain adjustments, it could possibly work, with specific abilities unlocked at specific levels, assuming you've gained them in the wild. Not sure how to justify it in story though, the ability lock out (I assume that our abilities are locked out for most classes due to the time bubble logic we did our various dungeons at a point that we were at that level, even if we put off Shisui till we're level 70, our character did it while we were still puttering about in the Ruby Sea, just like how we did the level 50 Culinarian quest before 2.55).