Still say the single biggest difference is understanding that winning is in and of itself a skill, not a product of skill. Folks get hung up on offense because it matters so much in the regular season, but tournament hockey is a completely different animal and must be approached with a different kind of mindset.
Will always means more than skill in a tourney. Best case scenario is your will putting you in the position to let a higher skill lever prosper, but the worst case scenario is trying to win in the playoffs via skill alone.
McDavid tries to get you 5 goals every night, far too often at the expense of his team. He has never changed, he has ripped thru and ignored a lot of damn good coaches in that town but management and their fans and media are so enamored with his highlights that they never notice that his type of game never wins anything. Nobody goes to bat for the coaches who try to instill a winning mindset, its just tune out and the next one thru the door.