You're giving hypothetical situations but how many of those actually played out during the season? In Dillon's case was he on the ice for a line change that ended up a goal, how many times? How many goals was he on for a 5-6 empty net goal? To measure Dillon's performance by shot metrics, who played alot behind Lowry, who isn't necessarily a shooter but a grinder, and a guy like Dillon who played in significant defensive minutes, doesn't always add up. Dillon was definitely a positive player 5 on 5 (2.9 GF vs 2.4 GA), as was Pionk, but they get ripped on here for shot metrics, being the primary defensive pairing. I'd ask someone to properly justify the anomaly between xG and +/-. And as a coach which one are you satisfied with. You know that anyone who plays more defensive zone than offensive zone is going to give up more shots, unless they are truly elite defensively, and still with the passiveness the Jets played with a lead, that's a challenge. Conversely you start in the O zone you get more shots. That's the nature of fundamental mathematics.
I realize it's not an ideal stat, but no stat used is without flaws. All should be interpretative in their nature.
Other than Dillon the top 5 in +/- were Ehlers, Stastny and De Melo, Pionk and the bottom 5 were Scheifele, Wheeler (who were both positive in shot metrics), followed by Vesalainen/Harkins and Beaulieu. Doesn't that kind of add up to player performance we talk about on here? The murky part would be Lowry with a +, with a - ES net result, and Dubois with a -, and a positive ES net result. But that would also be an indication of a guy who can score SH vs. a guy who was on a PP that gave up goals. Scoring SH is extremely difficult and takes talent so that reward is justified. Giving up SH goals is a sign of laziness or ineptitude, and this was an area Scheifele, who was out there with Dubois, was justifiably ripped in. That would be my way of connecting the dots.