SCH probably upset because this means that generally speaking you will be deciding in your raid group between SCH and AST.

AST regen is (probably, idk) still worse than WHM and does not bring MND (seriously, MND vs PIE NEEDS to change) so you lock in WHM and by consequence you lose some SCH spots to AST.

Not to say AST didn't deserve buffs, but we do not have as many slots for healers as we would probably like.