What AST still needs

[Seraphor]

If they're not going to buff Collective Unconscious any more, perhaps that's what should get the MP regen.
Could even give more by holding it, making it perfect for transition phases. Basically work like UI for BLM. Huge MP ticks that you don't intend to use for more than a couple seconds, but if the situation calls for it, you can hold it to gain most of your MP back.

Also, given Gravity's buff... I'd be happy with Celestial Opposition not having a stun, if Gravity got a Slow.