a Friend of mine raids with SCH in high end content and has done so through all of coil up to T13, He's just replaced himself with an AST because parse for parse the party DPS increased by 500 with the AST there and not having the SCH. This isn't saying that the AST did 500 DPS but that party wide DPS was 500 higher on average over multiple runs. Yes AST healing potency is slightly lower than both WHM and SCH but in all end game content there is another healer in the party and that is the point. They are a little like the OT in a way, they don't need to have as much healing as the main healer their job is to strengthen the party. Stop looking at the individual and recognize that any buff to AST in serious content would likely mean there is no point in taking any other healer.