I still maintain Maurice is the worst currently employed head coach, but the impact a coach has is relatively minor to the talent he ices; in the words of the only remotely sane thing Don Cherry ever said, show me a Vezina winner and I'll show you coach of the year.
One might argue that Maurice took the President's Trophy winners and barely made the playoffs with them the next year, and that the Panthers are merely doing close to as good as they would have done last year if they didn't run into the mother of all goaltending high rolls (.970, was it?)
As for the "playoff choker / playoff performer" thing, I've found basically zero evidence to suggest this is anything more than short term variance. If it is correct to say Austin Matthews is horrible in the playoffs, it's correct to say John Druce was the greatest goal scorer in history during the playoffs, and I'm not prepared for that.
And a similar analysis of "clutch performance" during the regular season showed the same thing -- there's no evidence to suggest a player's performance magically gets better or worse during clutch times. If there IS a "clutch power", it's not reproducible year to year and there are about as many clutch performers every year as random chance would suggest.
It seems like there are some players that can elevate their games though under high pressure situations. Marner and Matthews appear to have solid playoff numbers but their stats in game 5's, 6's, 7's and primarily elimination games are piss poor. That indicates that they have trouble preforming under pressure. Contrast that with Patrick Kane who while he has more playoff games played, has basically identical PPG stats to Marner and Matthews. But some of the best game 5, 6, 7 and elimination game stats of current players. Which indicates that he has the ability to elevate his game when the pressure is on.
We can pretend that the pressure doesn't get to some players and that others don't thrive under pressure but that is just not the case in literally any other workplace scenario. Why would it be nonexistent in sports but exist nearly everywhere else?