I can see the rationale behind Shuffle (it is frustrating to draw the same card) and “card nom” as an additional way to recover MP (other healers have 2 reliable methods of MP regen). So sure, those are interesting ideas and I’d be fine with them.
I agree that the AST in noct stance is just not as effective imitating SCH as diurnal is imitating WHM, but i honestly don’t think replicating SCH barrier heals are the solution. SCH’s fairy pet also provides a lot of free healing that just isn’t available for WHM and AST, so you’d probably want to focus on that instead of the barrier. It would solve the MP issue better (leading to more dps-to-burst-heal rotations) without completely usurping the strength of the WHM or SCH job.
Otherwise, some of the buffs for the damage spells are interesting but unnecessary or of small value. Slow on Gravity (or a DoT) would be nice and lore-appropriate. AST damage is the worst amongst healers, but it’s offset by the cards. There is a lot of RNG there but it’s not too much of a difference and you generally get a couple good draws over the course of a dungeon/fight. You won’t output damage like a SCH or WAR, but it’s close enough to a WHM that I don’t think it matters.
Similarly, the healing doesn’t need any more buffs. Yes, the stances aren’t as good as WHM or SCH, but it’s not intended to be a replacement for those classes. It’s meant to fulfill their role as main/raid healer in 8-man content and the AST does that well enough.
I also see no need to buff malefic simply because it gets replaced with malefic2 later. All the healer spells are like that. No WHM uses Stone II once they have Stone III and nobody uses Ruin when they have Broil. Yes, it should probably change, but there’s no reason to improve AST’s malefic specifically and not the others.
As a side note, I don’t see any point in adding new abilities unless you’re hoping these changes come out in the next expansion. At which point, I’d suggest other abilities that play to the meta than playing catch-up to the other classes (who will gain new abilities that make them even better).