You aren't incorrect, though, there are other factors in what you mentioned. SCH's main form of damage is DoT, so they have to wait for the full potency to be applied, in addition to their filler spell having the lowest potency. Plus SCH has the lowest base heal of the 3 healers, they don't have a second tier heal, and they have higher MP costs. But combined with oGCD heals and the fairy, the kit works effectively.
WHM, and to a small degree AST, uses HoTs as their main healing gimmick, they have the strongest base heal, the strongest second tier heal, and various AoE heals. Practically all of their healing spells are able to be buffed, and at later levels have decent MP management. Their DPS is also the strongest, with the strongest filler spell and the strongest AoE.
WHM main issue isn't their healing kit as a whole, per SE, it's that healing is all they offer. You are correct that at the current time DPS is all they can offer. But they have the best burst of the 3.
I only suggested this since the CC skills are just awful, and shouldn't take up a slot that could go towards a more useful skill. SE removed heavy from a lot of skills and made it a role action, so why not do that with bind and sleep. I am all for giving them back Protect, since as it is now, it's basically pointless.
