If Marner is not on a scoring line, he has no use on the team. He's a puck possession player, and you have other better options for that role.
I could see an argument bringing him along as an extra forward because he can fill in if a point producer goes down. But the problem is in tight checking playoff style hockey he's pretty useless. I would bring Toews over him.
Marner doesnt just excel at possession, he dominates scoring chance differential as well, even more so in the playoffs.
I'm not gonna hold it against Crosby that his team got wrecked by goaltending two years in a row while they were clearly the superior team....but I will hold it against a bubble guy like Baral who got embarrassed by Crosby all series but benefitted from having Varlamov instead on Jarry between the pipes behind him(and a support group that actually showed up to play). Barzal is going to be facing players of Crosby's ilk and getting run over all series wasnt a good take.
I dunno, maybe I just see things differently from you.
Marner is legitimately a top 3 RW in the entire NHL. Not only is the one of the best PK guys in the league (probably what nabbed him those Selke votes) but his numbers across the board are off the charts.
Even if you wanted to attack him on his playoff numbers, its tough as the Matthew/Marner combo are so good defensively that the other team still has a negative goal differential against them. Over the last two playoff years:
Matthews/Marner 5v5:
GP: 12
CF%: 55.53
SF%: 59.47
xGF%: 66.98
Goal Differential (GF%): 65.40
Despite all the posts hit and big saves against them, the reason that last number looks so good is that they absolutely wrecked the other teams offense with their smothering defense and takeaway ability. If every other player on the Leafs had those stat lines, it means the team went 16-0 on the way to a cup....the numbers are that good...and they have gotten unlucky.
It's why I ask folks around here to be careful with the hyperbolic talk about the two top dogs around here.
...and I'm pretty sure the Canadian brass can also see past small sample sizes and the nuance of those series.
Marner is an absolute stud of a player who dominates against the best matchup players in the league. Give him that bigger ice and I think he will thrive.