SCH's one of my favorite subs on RDM, too. Far, far, far from useless since it enhances the job's black magic side fairly well and you've still got some status cures if the situation calls for it, too.
Anyway, if he's changing gear around that could affect his max HP, that'd also alter Sublimation's output. He probably thinks /SCH sucks because Sublimation doesn't stack with Refresh. Not an uncommon sentiment, but I'm kind of glad it doesn't.
Violence good. **** bad. Yay America.