Her big schtick is raw output. If you look at her ‘gimmick’ as doing damage to heal and then chalk that to “oh it’s not much damage” then you’re looking at the wrong numbers.
When healing is based off damage dealt, then the damage should be ‘meh’ otherwise they completely outclass a damage-focused role in favor of a hero than can heal AND deal damage. Esp since said damage doesn’t consume mana.
So, functionally, she has some of the best raw burst healing potential, but a lot of players generally don’t put themselves into situations that need that sort of thing as a good thing for winning games. Usually the healer offsets poke damage and then has a few utility effects for making 1 dramatic turn-around moment or by having cc to lock-down an enemy target and press a numbers advantage with more bodies – if players don’t take damage, they don’t need heals, so killing an enemy team is better for mitigating damage.
A good chunk of the game has enabled spamming a lot of poke damage and whitemane doesn’t so do well against poke compared to other supports. So when it comes to mitigating how they expect to play on top of the potential burn-out she has for dumping all her cds, it can feel like she’s a “bot” for players that don’t pay attention to half their complaints.
IF a team where in a situation where several heroes were taking a large chunk of damage (but surviving) then her raw burst seems super handy, however, usually only one target gets the bulk of the focus, and a number of other healers have the tools to save 1 ally while then having cc or pve or something else that whitemane was built around not having – esp since there’s still some fear of the double-healer meta and she has to be ‘balanced’ around those sort of concerns to not completely stagnate the gameplay.
If you watch replays for casual play, if one hero gets isolated, then everyone else stands back to watch instead of going in to help, so her capacity to target multiple characters doesn’t really help compared to a reghar ancestral or an anduin pull.
Furthermore, a lot of players generally fear considering a second healer (despite how many times they may lose to it in qm/aram) whitemane only gets her fanatical following if she’s allowed to have a lot of, well, OP moments compared to other characters on her own, so testimonials in that regard can be less-than-honest regarding game balance, and being less than that is then “boring”
I still have a decent w/r with her, but I generally don’t play her (pre and post rework) because unorganized players are too stressful to try to enable her when similar results can be posted from easier healers that compliment the cowardice of common play. If I can’t rely on allies to peel, take camps, etc etc, then having a hero built around potential aoe burst, no pve, conditional self-sustain, and so on, then it takes much less effort to simple play another hero instead.