This is post of the year for me, well done sir.
As a fan I also sometimes question McD and I will certainly do so if we for example lose to Baltimore in WC again this year, but your post perfectly sums how valuable McD is and how in fact all comes down to 13 seconds.
Having said that, if he doesn't get it done this season or the next one, I'd try something else for the sake of trying something else. If fact, if we don't get to SB this year, I'd love Sean to say that if the team doesn't get to SB next year, he will step down by himself. It never happens but that is how I'd do it.