Is there a reason why WHM is the weakest healer in all fields?

[Supersnow845]

That would be fine if WHM had any strengths to leverage but they don't. Their spells cost more for no reason, their MP sustain is generally worse than that of SCH or SGE (not sure about current AST), they have fewer and less powerful oGCDs than the other healers, their mitigation is weaker. What strengths does WHM really have over the other healers?

WHM does in the modern game have the strongest MP economy but that’s really not much to leverage at all

In every other facet of healing it’s the weakest option