SE has shown they want to avoid any sort of complexity with Healer DPS, regardless of what forum ragers cry about. Give SCH and the other two more options for damage dealing, and all of sudden:

“Where’s your Shadowflare?”
“You aren’t refreshing all of your DoTs or you’re clipping too much”
“You aren’t using your DPS skills properly”

You give healers better more intricate tools for dealing damage, and sure it will make things more fun. But it also raises the expectation for Healers to not only DPS, but optimize their DPS efficiently. Granted, myself and many others would enjoy this optimization, but that does not align with SEs current goals.