Here is my take on AST.

The Job has potential, and there are moments when I am healing I feel fully in control of the situation, however this is providing damage intake is not massive. When I heal with WHM or SCH it just feels like I am always in control. What I notice is what others are stating. AST feels weak for some reason. I do find myself struggling at times. However when paired with a WHM I feel just like a WHM/SCH team. One compliments the other. In 4 person content it really depends on the group. If dps is fast I can sustain the healing. If dps is lacking then I find myself licking and choosing who and when to heal due to mana conservation. I am still intent on sticking with the job as I think it is heading down the right road, but honestly at this point I do think the job needs some help.