Basically everything that Rawrz just said.

To reiterate, I recommend forming your opinion based on your personal experience with healer jobs at the same level; if you judge based on how other players do, you will not get the real picture. There are simply too many players out there setting poor examples, and they are steering you wrong if you think that SCH or AST are at all lacking right now.

There are legitimate reasons why some WHM players are expressing concern over how the other two healing jobs are steadily encroaching on their niche. I don't think that WHM needs massive buffs or an overhaul, but I do think that WHM needs to be examined for tweaks in light of the fact that they are no longer the only healer that brings multiple regen effects to the table (their old niche vs. SCH's regen effect being tied to Eos) and that raw HPS is not necessary or desirable beyond what is needed to clear duties. WHM works just fine, but IMO the job has lost a little bit of what makes it unique aside from having the easiest kit.