Originally Posted by
Economizer
This isn't something I commonly think of... If Scholar gets Cure V, they'll probably get Accession for it, won't they? I don't even want to think about the balance implications around this.
Convert is not that impressive. As it has been said by many intelligent people here, in some depth, subbing Scholar is generally a bit more impressive then Convert AND self Refresh. Nerfing this unnecessarily makes Red Mage a weaker sub, which is also a major part of balance.
Ninja has other things it gives that aren't job abilities. So does White Mage. But Divine Seal is pretty useful, considering that many of the other buffs White Mage gives as a sub aren't things Red Mage can generally make use of (ignoring White Mage's substantial spell list). Of course, White Mage gets buffs to it at higher levels that make it more useful to cast.
But, like I said in the comment you quoted, I believe that like stuff like Divine Seal, Red Mage should get a buff to Convert. This retains the incentives to sub Red Mage - particularly for Black Mage which gets the most usage out of subbing Red Mage for Convert, while giving Red Mage a very fair buff to Convert.
If you still think that Red Mage getting a buff to Convert is an unacceptable better solution (you don't necessarily have to agree with the numbers I provided earlier) then gimping everyone who subs Red Mage, I think there may be more problems here then an issue with other people getting the same strength Convert that Red Mages main jobbing the ability get.