Honestly I think Provorov isn't anywhere close to Marner or Werenski.
Marner, Werenski
Hanifin
Provorov
I think it's probably something like
Werenski/Marner
Provorov
Hanifin.
The calculation for Marner/Werenski today is the similar to Marner/Hanifin as at the draft. Taking position, organizational need and size into consideration, Marner likely has a higher absolute peak than Werenski. Marner at 100% realized potential is better than Werenski at 100%, because you're talking about an absolute franchise forward, Patrick Kane type guy. But if you think Marner doesn't hit that peak potential, and the closer he falls towards a Jordan Eberle type baseline, then Werenski becomes the more important player, because his range of impactfulness as an elite skating two way defenseman is greater than a small scoring winger.
2015 was not an easy decision to make, and I think we'll be watching a decade or more without a definitive answer.