We dont technically have a HoT healer, we have healers with 'some" regens.
WHM being the closest, as they can stack medica2, and regen.
(Though their mechanics arent really built on HoTs)
Saying "we have it covered" is like saying DPS having Second Wind has healing covered.
But i do agree we need some adjustments to prior jobs, who borrow mechanics, in order to fill their own mechanics out, so that those mechanics can get a playstyle in and of itself.