Do you have any idea how much work it takes to create a new job from scratch? You need to create an all new weapon type and create several weapons across the levels gained through it, new splash art for the job, fully animate and add effects to upwards of 30 different actions, write a job story to introduce the new job and program in all those quests, create a new PVP playstyle for it as well, create new pixel art of it for deep dungeons, design a new icon, need I go on?
Let's not forget that it would also be added at level 80, meaning the player would need to go through everything up to Shadowbringers before accessing this minimum DPS new healer, something you were adamantly against a page prior, yet now you're suddenly in favor of it?
You know what it takes to make CNJ, the healer available at level 1, able to fulfill that role instead? You copy and paste WHM's abilities over to CNJ, add CNJ as a class that can equip all of WHM's equipment, and replace a handful of actions with traits that provide a flat potency increase to your DPS buttons, something that can be done in a matter of minutes. The only remotely challenging part about this is ensuring the potencies are balanced, but even that requires a very modest amount of white box testing. As someone who works in game design, I can tell you that we're talking a difference of 10s of thousands of dollars of work.
If you genuinely believe it's easier, less complicated, and more efficient to add an entire new job into the game exclusively for the purpose of creating an easy-mode healer for players who can't handle the DPS actions, then I have no idea what you're taking.
Maybe you're the one who can't tolerate the idea of someone enjoying a future WHM that has an engaging DPS rotation even when you are provided with something that is exactly as you want it to be.