Gard to say. If I was designing 6E I would poll about spell DC scaling and briefly explain it in nice simple terms. Eg old D&D you made your save 75-95% of the time. New D&D higher level you can fail 95% of the time versus a bad save.
Also point out monsters are in the same boat. You foukd skip that part I suppose but if it blows up in your face.....
Personally I'd reintroduce 4e Roles as Monster Traits.
Most monsters would be standard monsters.
But some monsters would have Monster traits that display their focus.
And you as a DM could switch Combat Role, Social Role, or Spotlight role freely between them.
Like a Legendary monster gets Legend Points.
So you can swap a Adult Dragon from a Legendary Soldier who can spend a Legend point on Resistance to save on a failed saving throw to a Legendary Striker who uses Deadly Strike to make a hit into a crit or Legendary Controller who can cast Counterspell via Countermagic or Debilitate to give the target disadvantage on a save