The problem with your supposition is that the criticisms are identical to those of analysts who have coached and played. I've played and coached at the Div 1 level. My wife, as such, has less knowledge than me. But she has watched plenty (dating when I played, married when I coached), and we have been season ticket holders for the Islanders and Thrashers before coming here. If she says a car is blue, she need not have painted the car to know that it is blue. Furthermore, the points made were not in the 'play Mackinnon for 40 minutes' category, rather on distinct deficiencies also mentioned by professionals.
Winning at every level sounds terrific yet it means nothing. Minor league hockey might as well be a different sport than NHL hockey. One or two stars will win you a minor league title. So one coaches around that notion. Just like an AHL player being terrific does not necessarily translate into the NHL, being an amazing ECHL coach does not automatically make a coach NHL material. Give me some specifics: What in-game strategies can you identify from specific games that would indicate Bednar is a superstar coach? Why is it that each and every Bednar NHL team has been terrible at face-offs? Why is it that it took 3 years for Bednar to come up with a D-Zone exit strategy? Why is it that for 8 years, this team has been unable to clear the puck? These are all things supposedly coached in practice.
I've got another dozen or so hockey coaching/teaching questions for you, if you like. However, there is a distinct difference between causation and correlation. Being part of a winning team need not necessarily mean that one caused it.