Okay all I'm hearing from you is...
Players: "Hm, I could see xx skill being useful if xx were to happen.."
You: "Nope, can't be stronger than my job"
Players: "But.."
You: "NOPE."
I don't see why AST can't be comparable to WHM/SCH. We may be able to change our type of healing but we're LOCKED into the stance during battle. I'd agree with you that it can't be as potent if we were even remotely able to change in battle. Like many have said, however, we want to be comparable and unique, offering something new or a comparable style of healing, not necessarily being the same as WHM/SCH with the same everything.
1. Collective Unconscious (like you said) costs nothing to cast. While it does have a higher duration than SCHs sacred, you don't end up using the full length of it. The fact you have to stay in place for 18s makes it utterly trash. All you have to spend on SCH is 1 stack of aetherflow for the same % reduct + time you'd actually keep CU up + you don't get rooted. On the WHM Asylum side, yes our CU has 50 more pot, but it has a lower duration than WHMs Asylum (and again, you have to stay still, which you can't for the full duration 95% of the time).
When you take a step back and realize that CU is worse than a lv 45 skill AND a lv 52, at level 58...it's kinda hard to see it in a bright light.
2. Celestial Opposition. It doesn't do much. For the effect it gives, the CD is too high in most people's eyes. A 4s stun ('cuz you know whm didn't get an equivalent in holy) that runs on the same timer as all the other stuns so might as well be useless. +5s to buffs is decent if used with full raid AoE balance, but again, it's not 150s cd decent.
3. Gravity is a crap aoe really. Might as well be holy, except oh wait, it doesn't give a debuff in any way, shape or form with it being almost the same exact skill. Blind, Stun, Silence, anything at all would be nice really for a lv 52 skill (vs WHMs lv 45 aoe stun and SCHs aoe debuffing/dot-ing).
I really see no problem with the potency of heals considering we're meant to be faster casters with our insta-cast aspected benefic and our trait for insta benefic II.