Yeah I agree that WHM has kind of lost its identity. AST has been on WHM's level for some time with their various buffs, and that's probably how it should be, honestly. Content is balanced around the idea that all healer comps should be able to handle it, therefore AST has to be able to heal just as well as a WHM in any particular fight running AST/SCH. Whether that meant outgoing damage was lessened, rendering WHM's extra healing unneeded, or that AST was brought up to WHM's level of healing power, which is what ended up happening, both cases highlight the issue that WHM simply doesn't bring anything else to the table while the other two healers bring a lot of utility.

Their strength of 'raw healing power' would've disappeared with the addition of any other healer really. It's why I'm hoping for some kind of utility for WHM in the expansion that gives them a new identity that actually distinguishes them from the other healers.