Next healer class released should be

[BasicBlake]

They could just make it a bolt-action rifle, or a single-shot grenade launcher. You'd still have "cast-times" but it's just an animation of your character reloading. And if it's one of those two now you have a way of justifying different ammo types, i.e. flame rounds vs healing salve shells for a grenade launcher.

If the devs were that worried about the auto attack tipping the scales they would shift power from other parts of the kit. Just like every other class in the game. You shift power around so nothing is busted, take red mage resurrection tax for example. If these all powerful healer autos are gonna be that strong they could make their dps abilities weaker to make up for it.

There is also not much in the game keeping you from auto attacking a boss as a healer either, other than you should be casting lol. At savage level, and as red mage, I can spend almost every every encounter in melee range to get autos off except for certain required mechanics and the autos add trivial amounts of damage.

So if auto attacks are the big hold up here... Why would you be idling enough to get that many autos in to begin with? Your encounter analysis would be shaming you every encounter to hit more buttons.