Raising healing requirements for newer content alone won't also improve older content

[Sani2341]

Other games do it with difficulty sliders. And we already have them. Problem is that normal actually is very easy. And then there is easy and very easy (never tried it but I can only imagine lol). Give us hard and very hard and tie an achievement to it. Done. The PotD treatment, basically.

How would a difficulty slider make playing solo duties as a Healer more engaging? Esp. as in at least half of them it feels like there's no point to healing the npcs(if there are any).