How could you do this to AST?

[KDSilver]

For example those sprites who tetter healers in amarout, taking 0 damage will block that healing down ability, while ofc in dirunal you take damage get that debuff and now your in stress healing with the healing down debuff

You can use so many ressources as AST that this healing debuff is like it doesn't even exist, DIU or NOCT, it doesn't matter, that's not really an argument.
NOCT is not weak. It's mathematically weaker than DIU if we take number alone.

Celestial Opposition for example :
Noct : 200 heal + 200 shield = 400 potency heal.
Diu : 200 heal + 100 hot for 15s = 700 potency heal.

You gain 300 extra potency heal from the regen.

Shield are strong for what they do, which is, mitigating incoming damage.
A regen will always be more interesting mathematically if damage you take will not kill you or stress you (I'm taking about big waves of damages).

That's just all really.

ast as is the hybrid healer like how a rdm will be a mix of a white mage/blm their heals are decent but not that strong to a standard whm

His hybrid playstyle doesn't make him have a "decent" healing. It's as strong as WHM, if not stronger sometimes.
The only thing in favor or WHM is Cure III spam. And this one really niche so...