A large issue AST has the is complete lack of emergency skills, or rather, raw potency. It's similar to how SCHs at level 50 were. If everyone is playing without making mistakes, AST can do fine. The problem is, when things start to go REALLY wrong, AST has no real power to recover from it. AST is also currently the only healer with a cooldown that will actually CAUSE WIPES. Because they are just so powerful they have to have that 25% potency reduction.

Being able to apply a fairly respectable buff when literally the stars align is not enough to justify their impotency. You need consistency and reliability from someone in the healer slot, not be reliant upon RNG to bandage your class' shortcomings for 20-30 seconds. I love AST, but there are some serious faults and annoyances that are GUARANTEED to get them excluded from true raid content. They just don't earn their spot right now, even if you do have the skill to play them perfectly.