I got a random idea, just for the fun of aesthetics alone: what if AST worked like an actual tarot reader and the cards act similar to NIN mudras? each seal has their own Draw - Solar Draw (Balance and Bole), Lunar Draw (Arrow and Ewer), and Celestial Draw (Spear and Spire) - and depending on which ones you draw, you get a different spell effect until/unless you next Draw. This could also help with button bloat.

So for example, you Draw:
- solar seal alone: Malefic turns into Combust
- lunar seal alone: Benefic turns into A. Benefic
- celestial seal alone: Helios turns into A. Helios

- solar + lunar seal: you can cast Celestial Opposition
- solar + celestial seal: you can cast Earthly Star
- lunar + celestial seal: you can cast Collective Unconscious

- solar + lunar + celestial seal: depending on the order you press them, you can cast Divination, Neutral Sect, or Macrocosmos

You'd be getting 4 new buttons (3 seal Draws + not-Ninjutsu to proc the spells from), but condensing 9 others, so you'd actually have 5 less slots in your action bar (not counting the ones that could be deleted, like Redraw or Astrodyne). All that while not touching the standard Draw to keep buffing allies, though I guess its cd or buff duration/potency may need to be adjusted.

As I said, it's just a fun idea, please don't burn me lol