A question: What makes a Healer "easy/simple" or "hard/complex"?

[Silver-Strider]

Though I'm not quite sure how you mean for Succor to work here. Like an AOE Iron Jaws that also is an AOE party heal?

Pretty Much.

though I'm not sure what "but turns the ability into Fester" means? Bane turns into Fester once you use it?

Think of it like how SAM's Ogi Namikiri turns into Kaeshi: Namikiri after use. You use Bane and then the skill changes to Fester in a similar fashion.

Just make Blessing into Indom?

There's a few reasons I didn't. For the proposed Fairy Gauge to work well, there needs to be more frequent usage of Fairy Abilities. It's why I cut the CDs on Blessing and Illumination/Covenant in half during the Fairy Ability changes. With the abilities also being stronger than the current forms of the skills (Whispering Dawn is currently 560 total potency to my proposed 600 potency, Fey Blessing granting a Shield effect under Selene and Fey Illumination/Covenant provide 15%/8% buffs as opposed to the 10%/5% buffs) as well as the change to Succor to make it useful to maintain DoT uptime, and by extension restore more gauge via DoTs, I felt it was fine to remove Indom.

Though I'm curious which Faerie you're using during Aetherpact?

Correct on the Benchwarmer Fairy. They would tether to your intended target and the other would continue as normal.

I'm kind of curious if SCH would be unable to effectively heal if they weren't actively damaging

I attempted to mitigate this issue as much as possible. Succor refreshing your DoTs to allow the Fairy Gauge to continue to accumulate while you healed, Dissipation allowing a free Fairy Ability usage, the buffs to the Fairy's skillset, Bane providing Mitigation, Shadowflare becoming a secondary Sacred Soil but instead of mitigation/regen, provides more healing received/Max HP, etc. was all an attempt to make SCH able to prevent that emergency scenario from happening in the 1st place. I even considered making Addlo shield breaks proc an effect that turns Ruin 2 into Ruination that provides 10 Fairy Gauge on usage but that was too much like Toxicon for my liking. The only other things I could consider was buffing Emergency Tactics to provide Gauge and give it 2 charges or put an effect like DNC's Espirit on Chain Stratagem so that the party would provide SCH with more Fairy Gauge as they attacked while the SCH focused on Healing.

Though it doesn't change AST's GCD game...maybe with actual interesting Cards, it wouldn't have to...

That was my thought process as well. AST never really had many attacks to start with, just the 2 DoTs (3 if you cross classed Aero 1), Malefic and Stella. Stella, however, lost its main purpose of being a 1.5s cast time ability over Malefic and the Heavy debuff hasn't really seen much, if any, usage in recent times that it would need a rework to be of any use to AST and while I'm fine with AST getting Stella back to break up the monotony of 1-1-1 Spam for them as well, I can't confidently suggest anything for them since I'm not sure what the class really needs to be engaging for AST mains again.