Nope. A mishmash of unbalanced monster skills that don't form a coherent rotation and can't be used in any relevant content does not count as a class/job. (That's the bloody issue!) They would, in my example, literally design one full job including job quests plus some disconnected skills for the side content they have planned. Bard is not two classes in one just because they have Perform skills.
Why? Because Limited Jobs were a bad idea to begin with and any suggestions to fix it are aimed to not make things worse than they have to be. I know the devs have a tendency to stubbornly ride their mistakes to the bitter end (Diadem) but that's really not necessary. I don't believe that getting the best possible outcome for Blue Mage will spark jealousy in those who play other jobs, because Conjurers got their mount quest and Bards got their Perform system without any such controversy.
Situational stuff was part of the BLU identity, was it not? The player using Bad Breath rarely could also be achieved by giving it a resource cost that makes it worthwhile only in AoE cleave situations. For single target you'd use some other monster skill. And another skill for sustained multi-target, etc. The filler skills would also be learned from monsters so I don't see the problem. If I go in the open world and fight regular monsters of my level, the skills they use are often quite unimpressive and would be perfect as fillers without any nerfing.
Tbh, implying that BLU must be overpowered in order to be "true BLU" and dismissing any counter examples as "not true BLU" pretty much fits the definition of the No True Scotsman fallacy. The only things that actually seem to define a BLU are that 1) they can learn skills from monsters and 2) they fight using skills learned from monsters (Blue Magic).
Blue Mages, as their name implies, focus on Blue Magic, a special subset of Magic that allows them to use attacks otherwise exclusive to enemies. While an odd choice, Blue Mages often have a wide range of usefulness due to the varied spells they gain. Blue Mages usually learn Blue Magic by having enemies (or occasionally, another Blue Mage ally) use it on them, but some games have other methods to learn their magic. http://finalfantasy.wikia.com/wiki/Blue_MageBlue Magic (青魔法, Ao Mahō?), also referred to as Blu Mag, Enemy Skill, Blue Bullet, Ronso Rage, Lore or Blue, is a skillset consisting of abilities used by monsters. Most of the time, a character who can use it is known as a Blue Mage. It first appeared in Final Fantasy V and was a staple in the main series until Final Fantasy XII. The exact method of learning Blue Magic has varied, but all involve the magic being learned from enemies. http://finalfantasy.wikia.com/wiki/Blue_Magic