Every problem with the current iteration of healers.

[Datara]

it's just people don't like its cards

And that's exactly the problem.
If the specificity of the healer isn't liked anymore by the actual players of the class since it started then there is probably something wrong with it.
I'm ok with healers chipping in to dps a bit, but cards focussed solely on increasing damage is a brutal downgrade from what it could do before.
Dps have enough damage buffs already between them, a healer would be more welcomed with keeping people alive or facilitating the fights with mp regens.
AST went from a deck of trump cards to a brick.