So far, I like AST a lot, but as some people have brought up, there's a few discrepencies:
Nocturnal stance. While I see where people are coming from with regards to thinking it's weak in terms of pure potency, I think a bigger issue with it at the moment is because of its weak potency it offers very, very little in regards to opportunity cost. Using aspected benefic in noct stance gives you a brief instant shield, yes, but that shield is typically eaten up by a single auto attack shortly thereafter, before your GCD has even worn off. This is in contrast to scholar, where throwing an adloquium out will buy you plenty of time, especially if it crits.
What I'd like to see for Nocturnal Stance is a passive buff along the lines of "Moonlit serenity" or some such, that stacks up every two seconds, up to 5 stacks. Each stack grants your subsequent aspected shield an additional 10 potency per stack. At maximum stacks, aspected benefic would actually be slightly stronger than a non-crit adlo (And a crit adlo would be more powerful than aspected benefic) and it would give AST the niche of having a stronger AoE shield (190 potency) than scholar which is already predominately single target based. (Though that has changed some in the expansion) it would discourage spamming your aspected benefic (Which you shouldn't do anyway) and encourage more smart usage of it. It would also give noct sect a decent "power" button to use, as that's currently a big thing lacking for AST, and it would appear they want Noct to be more of a heavy hitting healer. Just a thought, something that would give Nocturnal a buff without just straight buffing it.
I also think they need to make Celestial Opposition and Time Dilation change their effect for Noct's shields slightly, instead of increasing their duration (Which is a straight benefit for diurnal regens), increasing their potency by a certain amount. (50 potency for Celestial Opposition, 100 for Time Dilation? Not sure.) Also Collective Unconscious. The fact that we have to channel it. What are you doing SE. If they want the same feel, allow us to perform actions during it, but we must stay within the bubble for it to remain.
The inability to use Spread out of combat also drives me up a wall. I see no reason for it, other than to make it inconvenient to try to set up effective combos before a boss pull. I would love to be able to do an expanded royal road with spear to maximize its effectiveness, but it's impossible to consistently set up. That's fine mid combat, it's a part of the class, but the fact of that matter is that your very first card draw is going to make far too much of a difference. Drawing a spear, balance, or arrow bumps up everyone's efficiency during their opening burst to the nth degree, while drawing bole, ewer, or spire is almost entirely worthless. It's not a good feeling.
This is all speaking in the hypothetical, and don't get me wrong, I don't think AST (And particularly Noct sect) is necessarily bad right now, but I do think it needs a minor buff and more synergy with its own cooldowns.