Why not make healers like Mercy from Overwatch?

[Physic]

We did. It was in Heavensward and it was called Astrologian and it was awful. The only thing it could do was roll a d6 and hope for a Balance. If it got the Balance it was great, at all other times it was a subpar WHM.

except it must not have actually been awful by the time stormblood happened because it was a top healer in savage. Just because you personally don't like a mechanic in a job doesnt make it bad.

as to the OP, mostly because, the current stance is that all roles must have roughly the same capabilities, and balancing dps buffs versus dps isnt easy, since how well it performs depends on how well the team uses it.

i think its a problem, and would be better if jobs were diverse, but SE seems to want homogenization of classes.