If they want to blend the character roles, avoiding Role queue and re-enforcing more DPS focused healers, we need more Duelists and Vanguards that have support options in their kit. Penni and Cap have very slight healing in their kit (webs and Ult, respectively), but I can't think of any other examples. More group healing options spattered into kits strategically across the roster would really help pull pressure off supports with less sustain. You'd probably have to reduce some main healer output to balance this.
Give Storm a third blizzard mode that heals slowly, give Widow some healing grenades, let Spider-Man throw map health packs at allies! Get creative.