The most obvious fixes are:

AST:
Remove Undraw.
Merge minor Arcana into Draw. This can be done in multiple ways, assuming the card system doesn't get a huge overhaul:

1. Give draw an additional effect that grants 1 stack of "Minor Arcana" buff when activated. On 2 stacks of "Minor Arcana", the buff is removed and 1 card is auto-drawn onto the gauge. Reduces 1 button.

2. Alternatively, the effects of Minor Arcana is merged with each individual [Draw] & [Play] skill. Every other [Draw] will become [Minor Arcana] instead, which is essentially a regular Drawn card (Random card of Balance/Spear/Arrow/Bole/Ewer/Spire with seal) + the drawn card of the Minor Arcana (Lord/Lady of Crowns). The [Play] ability temporarily changes to [Crown Play]. [Crown Play] no longer activates around you, but is centered based on whoever gets the effect of the regular card effect. Reduces 2 buttons.

Depending on if the seal gauge changes, Astrodyne can be merged with Divination as one ability as a powerful buildup skill if Astrodyne doesn't get any new interactivity with the skill.

Synastry is a pretty unique ability IMO. It would be nice if it gets some additional interactivity in the skill's effect to justify keeping it around. Alternatively, I would not be against it if Synastry is merged into our abilities instead as a trait. Ideally Synastry would just be an additional effect tied to all our single target abilities with varying degrees of efficiency. EX: Targeting an ally with Essential Dignity gives a "Synastry" buff for 5 seconds, which can be extended to a maximum of 20 seconds. Targeting an ally with celestial intersection or Exultation can also apply "Synastry" with an additional 5 to 10 seconds, which can be extended to a maximum of 20 seconds.

SCH:
Merge Fey Blessing with Whispering Dawn or Fey Illumination since Fey Blessing is just a fairy AoE healing skill.

WHM:
Merge Divine Bension with Aquaveil by giving Divine Benison the additional effects of Aquaveil at lv 86. Honestly, WHM lacks skills in general and needs a proper re-examination.


SGE seems very streamlined already as it is. Eukrasia pretty much removes any GCD button bloat and can introduce 2 new skills with 1 button. Zoe, Krasis, and Soteria are all unique in their purpose and gives some dynamic healing optimization. All SGE needs is to make Kardia / Soteria more important and unique - which can be done with support-oriented DPS skills or through Eukrasia. That, and some more interaction with addersting and DPS tools when no additional support is needed.