I haven't done any Heavensward dungeons yet, but healing is still pretty erratic in the ARR stuff. I get everything from '3-mob pull tanks' which require no healing at all, to 'pull-everything-from-one-boss-to-the-next' tanks that require nothing but healing until enough mobs have been killed for the tank to survive a gcd without a heal. I have yet to acquire the 50+ abilities that facilitates WHM dps, so I am still on the outside looking in a bit here.

However, from my experiences thus far, I feel WHM is fine as is. The only thing I find myself wanting as I run content is an AoE cleanse. I would love if Divine Seal had an additional effect that makes your next Esuna cast AoE and making a recast unavailable until the effect of DS wears off. A lot of players want additional WHM utility, and that is one that packs a nice punch without OPing WHM. My only concern is the enmity it would generate.