After putting 50 or so games into the Whitemane rework, my opinion is that her AA build can heal significantly in a few niche situations. Other than that, she really feels lackluster over all. The effort it takes to be on par with other healers is excessive.
I do not experience the mana issues others complain about. I time my Qs with the desperation cooldown as much as possible, sometimes not even dipping under 70% mana for the entirety of a teamfight.