Perhaps I am not understanding OP's aim with this thread. If you want to play a class like WHM and AST, play WHM and AST. It is easier to buy a horse than it is to try to cover up a zebra's stripes and attempt to ride it.

As demonstrated by other posters, there's still plenty for SCHs to do in raids and all Healers are expected to DPS when possible. Do you want content to require more healing?