Overall
-Have the Cure and Benefic upgrade to Cure II and Benefic II. I also like Saffron's idea of Physick being a mini shield that upgrades to Addlo.
-Make a Eukrasia-like buttons for WHM and AST that turns Cure/Benefic and Medica/Helios into HoTs.
-Remove Repose, it's only useful in Eureka/Bozja, where it could be turned into a skill for those areas. (Most people don't even have this on their hotbars anyway.)

AST
-Make Draw and Play one button
-Remove Undraw
-If they're not going to interact with the cards, I would get rid of Minor Arcana/Crown Play. They're too random to be reliable but not random enough to be fun or charming. If they go back to ShB's version of Minor Arcana, they should make it one button.
-Celestial Interjection and Exaltation could probably be fused together where once Interjection's barrier is broken or times out, the target is healed (200 shield + 500 heal). Keep it at 2 charges.
-Fuse Neutral Sect and Synastry (and make it so the user can be targeted by Synastry for solo play).
-Fuse Astrodyne and Lightspeed. You automatically get the MP-Refresh and 2.5 second cast reduction but your DPS and Healing increase based on how many different seals you have (1%, 3%, 5%). The only issue I see is that it still wouldn't align with Divination, which neither button did anyway unless you held on to them.
-Remove Celestial Opposition and increase Collective HoT potency. Maybe give it a second charge?

Buttons saved: 10

WHM
-Instead of having two separated Lily buttons, have one ability that turns your next Cure/Medica into their Afflatus counterparts.
-Fuse Divine Benison and Aquaveil, providing both a shield and a damage reduction. Maybe add a third charge?
-Fuse Temperance and Asylum. Have it be an HoT, reduce damage, and increase healing ACTIONs potency. Also, reduce its cooldown and increase its AoE. >:v

Buttons Saved: 6

SGE
-Maybe fuse Krasis and Zoe? Target gets Krasis and you get Zoe.
-Maybe Soteria could go.
(this one was hard for me because I use to main SGE, so I know how everything interacts at a basic level)

Saved buttons: 3

SCH
-While it's useful, I think Dissipation could be replace with something that goes with the kit better. (Or have it affect your healing actions and not just spells)
-Get rid of the Summon Eos/Selene spells, make it so you automatically have a faerie out via a trait, and make a Pet Glamour Menu for SCH and SMN (and maybe MCH and RPR)

Buttons Saved: 5