I would argue the biggest issue for SCH now is that it's starting to suffer the same issue that WHM did in 3.x: lost identity. Its healing specialty of damage absorption is currently dwarfed by how much more effectively AST can use it with Nocturnal Sect.

Oh, and let's not forget that AST tops it in terms of raid support as well since no amount of damage a SCH can deal will ever top how many times an AST could use an AoE Balance in one fight.