It’s easy to be an armchair coach (I’m including fans, tv talking heads and former players with average skills) to give expertise advice to these highly skilled players. Plays develop with a split second decision has to be made so they have to rely on their instincts developed over years. They when interviewed may say the right thing to go along with the flow but in game situations their instincts will take over.That's the nature of sports. The Canadiens passed on drafting Bossy (a Montreal boy) because he was weak defensively and perceived to be fragile. Yes, Bossy is in the HHOF.
I think some people, including Marner himself, think he would be a better player if he shot more. Not saying he is a bad player now.