I don't think WHM or SCH need to defend their positions at all. If people are not running SCH+WHM on Coil then they're making it needlessly harder on themselves, though that's a personal decision of people as to the people they want to play with and compositions they want to run. I know this thread was intended as a joke, and I agree with the OP: I think WHM and SCH are both in a pretty good and balanced place atm and don't need much changing, though I'm interested to see where the classes go in the future.
