While AST is suffering heavily in terms of healing potency, it's currently the most busy healer at the moment.

When I play AST, I am constantly shifting my attention between the cards, the cDs of abilities, Damage opportunities and healing.

With this priority:
Healing>Cards>Damage

I am an experienced healer. I have the three healers leveled and ran EX with all three. And while AST feels week in terms of potency, it's by far the most engaging by virtue of the mechanics of its cards which fill its healing downtime with a non-dps alternative that still contributes to group success.

So I thought, shouldn't the Devs embrace the individual identities of the SCH and WHM as debuffer and damager respectively to make their gameplay distinct and unique?

Rather than broil spam SCH could focus on applying vulnerability and debilitation debuffs on enemies with a system based on analysing enemies and their weaknesses.

WHM already has a system that builds up to damage burst but could it be made more engaging with the use of different elemental spells.