What do you think makes Astrologian so strong?

[YusiKha]

The ability to go either way with Regens or Shields

Wait - the ability to be played alongside both healers, putting everyone on an equal playing field, is OP?

The ability to grant AOE shields along with a standard AOE heal

And people cast Helios?

AST's tale is a funny one. It started out with strong identity, undertuned, weak cards with terrible RNG on top of weak weak heals, so weak that it was a joke compared to the other two healers. Buffing cycles ensue. By the end of Heavensward it's a job with strong identity and super duper strong shields of every type. This carries into Stormblood, and with the addition of Earthly Star, it becomes an insane healing powerhouse without real rival.

Strong shields don't mean much. The game is balanced that the weaker shields are still enough to cover 'requires shield' mechanics, and shielding mechanics that aren't lethal is a waste of a shield.

Despite being less complex than SCH used to be, it was perceived as the most complex, scaring people away from it

So multiple layers of RNG and potency calculations, as well as no weave slots (1.5s malefic was only added in patch 4.3), is less complex than a 2nd DoT?

But also honestly, its main power comes from being able to have shields. Without the shield stance, it wouldn't really be all that special.

So AST should only be allowed to play with SCH then. Despite Nocturnal being the weaker of the Sects, it's very overpowered. Alright.

And if SCH wasn't on the back burner for once/toned down like it has been, it'd probably be there right along with AST. Or if they just gave SCH an AOE GCD that is the equivalent of Medica.

So it's not having the fairy skills be ineffectual and unsatisfying, the requirement of sacrificing your own DPS to use healing tools WHM & AST get for free. That's not what makes SCH less desirable than AST.
Instead, it's the lack of access to the worst AoE heal in the game.
Alright.