This would likely require more recoding of the way the spell works than they are likely to bother with. (Cure as an undead nuke in FFXI was never exactly efficient, for the record -- it was something that was always more of a novelty than anything else.)

Elemental wheels aren't coming back. As absurd as it is for BLMs to kill Ifrit with Fire, that's kind of the way it has to work, otherwise the class would be completely neutered in that fight, and several others. They want to keep every job viable, even if not necessarily top-tier, for every fight.