The pre-shield, post-shield idea is a specific scenario, and not the best example. It would involve a scenario where someone didn't get a shield until it was too late, and now the SCH has to get that person (or persons) back up to a reasonable level of health. The SCH could leave that healing to the fairy and AST, who could utilize any of the healing spells in his toolkit, and focus on keeping shields up, or if they are already in the middle of casting physick then the AST could step in to give their shields.
The fact that the Aspect skills aren't going to get used, isn't necessarily a bad thing, is it? The potency for AB and AH is lower than Benefic and Helios, and when comparing the Diurnal effect to the Nocturnal effect, I saw that the Diurnal regen was only 1.5x stronger than the Nocturnal counter-part -- and that's assuming your party members aren't taking damage greater than what the regen can heal. If the AST in noct is focusing on utilizing Benefic and Helios more than AB or AH, that should be a good thing. That's healing comparable to WHM cure/SCH physick, and WHM Medica (I'd say Succor but the whole shield thing gets in the way. SCH don't really have an AoE heal, and their fairy has a regen).
Testing the theory isn't just for a fun challenge, it's to validate that the problem with AST is more than just shields in Noct. Does anyone here really believe that a fix to Nocturnal Sect's shields is suddenly going to fix any other problems that we might come across in the job? What else are we missing because we choose to ignore an option, without backing it up to say "We've tried to make this work, and it just doesn't"?
This is in a similar vein of what I'm getting at. As I see it, the AST job is not meant to replace a WHM or SCH, and yet we're attempting to do just that. Rather than play to the classes strengths, we're attempting to shore-up the weakness of the other healer.
So far I've got one person to come back to me in all of this and tell me that they tried running WHM + Di AST in A1S, and the regen stacking wasn't enough. I'd really just love to hear more people at least try, and tell us what the results were.
Were regens not enough in specific content? What content was it, and what mechanics were you running into problems with? How did you get around it, or did you throw in the towel? Was your healing not up to snuff, what do you think would help? Are you certain its the job or the way you handled the mechanics?