Level 70 WHM here. I will say this, despite everything wrong with the job, despite it feels tremendously weaker and less engaging than AST, it is wui fun.

Holy spam is better than ever, Assize feels very powerful with a huge radius centered in you, and their DPS capability is outstanding.

Now, if you're not the type to take advantage of healer DPS, WHM is going to be insanely boring. Lilies is disappointing, Plenary Indulgence is hellishly broken (in a bad way), so you'll mostly sit there casting Cure II over and over. They have nothing outside of DPS, so ask yourself this:
Do you want to focus on damage and healing, or do you want to focus more on support and healing?