If we're going to use hindsight on the 2015 draft the clear mulligan to call is on standing pat at 4. Can't fault Hunter for being bullish on Marner, he was right. But considering it's documented fact that we explored dropping to 8 with Columbus, even at a very conservative 8+34+68 for 4 we go from
Marner+Dermott+Bracco+Dzierkals to
Werenski + Konecny + Dermott + Dzierkals
-assuming we took the same player at each slot. Who knows, maybe it would have been Rantanen-Dermott-Aho.
There was a big divide on the board (and in the scouting world) at the time. Conventional wisdom was that it was Hanifin/Marner/Strome (in some order) then a big drop, but there was some of us pushing that the likes of Rantanen/ Barzal/ Werenski/Provorov belonged in the same tier.
Water under the bridge- we got someone that's 50/50 for the HoF so it's hard to complain.