In a premade team, SCH is great IMO.
I've been running with 1 DRG 1 BRD 1PLD.
I can see why WHM may have trouble simply because their pro is big heals, but against a party with a SCH or SMN miasma cuts their efficiency in a half with an insta cast
SCHs shouldnt have an issue, you can negate alot of incoming debuffs with shields, heal on the run with lustrate and cover two sides of the map healing wise.