I've seen a black mage at lvl 50 who has zero idea on how to play his class. He would spam blizzard3 non stop and then randomly start randomly spamming thunder3 on single targets in aurum vale. I've even seen a dragoon that uses impulse drive...and then a full thrust, over and over. Just those 2 skills. You simply can't avoid these players unless the game makes a harsh check trial content when they learn a new skill. You'll always have players that simply have no interest in learning how their classes work.
Your way of doing it is basically just semantics. Plus, scholar and summoner exist. Going by the base class, scholar would be the one getting removed to make everyone uniform. You'd have to introduce a new guild for scholars and remove all their ACN skills because they'd just be clones. What would they even have in exchange? I'm actually pretty sure that it's the summoners who would rather have a rework and have actual summoner things to do instead of dots galore. Then there's the question on whether the smn should still have physick and resurrection when it's probably meant to be on sch first. How are you going to explain the cross class system? Pre-crystal jobs can cross class any skills but post crystal jobs can only cross class from 2 and it can only cross class from pre-crystal skills and only 5? Explain that by obtaining a soul of an ancient job user you now only gets to cross class 5 skills instead of 10?
If summoner gets the acn guild, their lore would not match at all, would we have to change the story? What about the gladiator and paladin story lines? Paladins fighting in the arena for money? Ala mhigan monks in uldah? Tribal warriors in pirate state? Ishgardian dragoons in gridania? Lost white magic practiced by low level magic users in gridania? Or black magic for that matter? Gridanian bards doing NO music until they suddenly learn it from some guy out in the woods? All of gridanian ranged military are bards? They're just 'lore' but they affect the system of levelling in the game. The job stories were designed to allow wild changes from the class lores that are based around the cities' lore and appearance.