It should be given consideration of course but not weighted so heavily to discount what Karlsson's been doing. Also perhaps Zeke only meant that Karlsson shouldn't be considered this year? Because his usage in San Jose is way softer than anything he had in Ottawa, its disingenuous to suggest that he is some sort of career-sheltered player and it leans into an ancient "4th forward" narrative that should've long been put to bed.
As for Rielly although he has taken more difficult usage than Karlsson this season, if we had Vlasic on our side I doubt this would even be the case, he does not have the most difficult usage on the team. Behind Hainsey and Zaistev by any metric and pretty on point with Gardiner, somehow despite being middle of the pack for usage on his team and playing less time than either Burns or Karlsson they are subject to criticism for taking on sub par players and Rielly lauded for his workload? Unless we're playing against all star teams every game and the Sharks are taking on the Oilers something smells fishy.
Rielly's having a terrific season and deserves to be in the top defensmen discussion at least of the year so far, but we don't need to try and cut giants off at the knees to show everyone how tall Rielly is.
a couple more things:
Rielly does in fact face the toughest even strength quality of competition on the team by opponent's ice time. His 29.76 es toiqoc does lead the leafs dmen (11th of the 144dmen with 500+ minutes), and by a lot over anyone but hainsey, who ranks 24th. Jake and Zaits are facing tougher competition than they did in previous years, but still rank well back in 53rd and 55th in toiqoc)
And I'm not sure why you think Vlasic would or should get tougher usage than Rielly. Vlasic gets slightly tougher usage (ranks 7th), but gets demolished in that competition (-7.4cfrel, -9.1xgfrel).
the natural comps between the two teams, based on opponents' ice time:
(i'll add rough cf/xgf averages in brcakets0
Rielly 11th (50.0pos%, -2.9rel) - Vlasic 7th (49.7pos%, -8.2rel)
Hainsey 24th (48.2pos%, -5.2rel) - Braun 27th(49.0pos%, -9.1rel)
These two pairs get legit elite top-pair usage, neither is doing especially well in it, but the leafs' pair is doing better, and Rielly clearly faring better than any of the others. And where Hainsey seems to be clearly dragging Rielly down, vlasic and braun seem more even in their ineptitude).
Gardiner 53rd (53.0pos%, +2.1rel) - Karlsson 77th (59.9pos%, +7.9rel)
Zaitsev 55th (51.1pos%, -0.9rel) - Burns 105th (56.7pos%, +2.2rel)
Jake/Zaits actually are getting stronger competition than usual, borderline top pair usage, but still well behind the top pairs. But they're doing quite well in this usage. Meanwhile Karlsson and Burns are getting strictly 2nd pair type quality of competition. Burns is actually only getting borderline 2nd pair competition. To his credit, Karlsson is absolutely crushing it against secondary competition, but still, imo you just can't call that a clear advantage over guys who are facing elite usage. But at least I see the argument there. As for Burns, his underlying numbers are only good, not great, against not even clearcut top-4 competition. Burns should not be in any Norris conversation, and never should have been.
But, like i said, it seems like SJ is finally figuring it out and dialling down Vlasic's usage (8th is tough but this guy has led the league by a healthy margin pretty much every year of the last 5), and dialling up Karlsson's.