Had the same conversation, you could see that at the end of the 3rd OT that the Duluth goalie was already struggling to stand up. At the beginning of the 4th OT, it was apparent the first time he went down that he could not go on so they replaced the goalie. Fanti made saves that Stejskal would not have because he was fresh. I am certain UND would have won in the 4th OT if the goalie was not replaced.
Looking at the UND situation, Scheel showed now signs of slowing down even in the 4th OT, He was getting up and down on the ice as normal. You cant fault them for keeping him in.
My only thought is Fresh goalie of the bench would have faster reflexes against players that were dog tired and moving slower than normal, Advantage Goalie.