AST was a failure from the begining, SE didn't know how to make a new healer and the new buffs and nerfs prove it even more. They basically killed WHM and SCH because they have no idea of how to balance them, AST shouldn't have stronger shields than SCH, and shouldn't have a stronger healing potency than WHM.

Cards are the only reason to have an AST in the party, and it's a good reason, there is no point in use WHM/SCH anymore since two AST would give way more utility, and they are better at healing than the other two.