Any kind of stance that involves a reduction to healing potency will never return. They got rid of that for a reason, and doing the same thing to tanks only goes to reinforce their decision to move in this direction. If there is to be any kind of stances for healers, it would likely involve preventing damage vs recovering from it. IOW shields and direct heals. However, a constraint is that some of what remains of what differentiates one healer from another is tied to those two healing archetypes. This along with SCH being the lock-in shielder has been a big problem with AST, which has lead to it and WHM leap frogging each other like anime rivals.

I don't think AST sects needs to go away, but I do think they should change what an AST does. I think current noct should pretty much be scrapped at this point, and should instead place a different effect on their cards. A mechanic the forces the AST to use both sects in battle I feel would be much more favorable to trying to give them the ability to choose which one. This just leads to staying in whichever stance is the most optimal. I believe AST could be really fun for a lot of players this way, but of course, not everyone would be on board.

As far as SCH and WHM go, I don't think they need any kind of stance switching. That type of gameplay could go a long way to giving a particular healer a unique playstyle which is what is desperately needed for them right now/