Not necessarily true, A DPS healer wouldn't kill WHM because this has already existed in the game in another format with SCH. Sure SCH doesn't have DPS skills that also heal, but they can DPS while eos provides a ~150 potency heal so essentially its the same thing DNC would do, they would just have more tools to recover while DPSing. In theory DNC will have similar healing/damage output to a SCH without the barrier aspect and perhaps a pro being a tad bit higher DPS, so they shouldn't replace a WHM on progression since WHM will be far superior at raw healing, and they will always be at risk because they will be meleeing; something WHM doesn't even need to think about.
However, that doesn't mean WHM doesn't need any utility, I agree that they need utility. Perhaps give them defensive utility such as making protect unique to them again by giving them the PVP version for physical damage, and shell for magic damage. Then they could add other defensive utility such as Blink which would increase the target evasion, and reflect/reprisal which would redirect a portion of the damage received. You get the idea basically defensive style utility.
