Considering WHM has 0 group utility, it's the BLM/SAM of Healer jobs and has the highest DPS potency of Healers to make up for its lack of utility; It's damage is its utility in other words. The inverse to this is that AST had the most utility and thus the weakest DPS of the Healers. SCH is the middle child in the equation, having more Utility than WHM but less than AST but has more damage than AST and less than WHM.