For SCH, I actually wouldn't mind a giant flying book for a mount. When airborne the glow can resemble fairy wings. Would love something angelic for WHM. How about a halo? A giant spinning celestial body for AST fully equipped with orbiting satellites would probably become my new favorite mount in game, easily.
Healers remain a backbone role though for sure, and comes with an the same unnecessary strain we humans typically place on ours. A back massage would be nice once in a while SE!
The comms are nice though and well appreciated from this healer.