Misshapen chair once said that if all healers get reworked into something more engaging, then one healer should stay the same for the players who like that kind of gameplay.
For those who enjoy healers as they are now, would this be a good compromise? Every healer who enjoys the endless Glare spam just stays on White Mage while the other healers actually get interesting damage buttons to press?
We've already got Gunbreaker with a damaging rotation that's far more tightly executed than Warrior, and if anyone complains about GNB being too hard, they're rightly told to git gud, or play a different tank, because GNB mains enjoy it like it is. New Summoner is practically a Simon-Says that can run laps around the arena while Black Mage is sitting there in their circle actually having fun.
The main issue this solution might bring is the White Mage mains upset about needing to abandon their job for something more engaging. Personally, I think they should re-work the "class" system, where for normal content, stoneless classes like Conjurer are viable and get bare-bones skills up to around max level. Decent output at a basic level, but without the potential that a Job has, which would encourage them to actually branch out and try White Mage.