...While not spoiling the fun
But are you not doing what you dislike about the traditional hockey community so much here, i.e. "i believe player X to be good, and therefore I reject your model/belief because it disagrees"?
You're going into this with the assumption that McDavid is the best in the world. Which is fine, but admit that's your assumption. You're not trying to debate who the BITW is, you're trying to pick and choose the stats and arguments to support your hypothesis instead of entertaining inconvenient refutations.
Is hockey more a team sport than an individual one, yes! But a continued under-performance when the pressure and focus are turned up from the guy who puts up crazy regular season highlights and numbers shouldn't be ignored, or mistaken for a PLAYOFFFSSSSS argument. If you're going to be the no-argument BITW then you need to prove you are better at winning than anyone else, and McDavid just has not proven that to the degree that there should be no question about his BITW status. Debate is healthy.