One problem I see with funnelling most of a healer's damage into buffs is that it doesn't fix them being absolutely insufferable to play through solo content on (basically the entire MSQ).

Personally, I'd want to see all healers do at least decent damage on their own and the buffers can have their damage supplemented by buffs while the ones without buffs can just have slightly higher direct throughput so it more or less evens out between them both.