Other than ast stealing sch's identity, the issue is the others need more utility. SCH had their taken, and they now...uhh... not really sure. AST does it better. WHM has more snap heals to fight back with, but that's all they have. A healer has to be able to heal enough to cover content though, or they are unusable, like original AST. If the other healers do not get some kind of utility, AST will always be better, unless its just made bad.