I should say for starters that while I do think that Marner's is by far the worst deal, there is a substantial advantage of getting that f'ing mess out of the way. If you look at how much of a strain it has been having on the fanbase there was little chance that this was not having an impact on the players at camp. For two years in a row they were going to have this massive spectacle and uncertainty as a black cloud hanging over everything - I think that takes a toll, and I think it causes additional wear at the start of a long season.
It's selfish when it happens. I can place a lot of the blame on the year before on management, as they seemed to just think they could wait it out with Nylander, but with Marner they had been aggressively bending over backwards to get this done and essentially had given the actual best offer to Marner months ago and all Marner was interested in was getting every single drop of blood out of them, so I can't blame management on this one. I hope the extremely crappy cap situation where they have essentially no flexibility doesn't remind the players of this all season long.
I am someone who thinks that when you give a player a - let's say - 5 year contract that you are not paying them for what they have done, but you are paying them for what you feel they will do over those 5 years. That's a tricky thing to do, and I feel that is what Dubas wants to do, but he is trying to do in a league that has always paid based on what players have done - and usually done based on raw numbers.
I don't want a GM paying for a team that hypothetically would have won last year, but instead paying for a team that will win this year.
Numbers are far from everything, but nothing drives me more nuts than hearing that someone who put up, say 85 points with two crappy linemates is worse than someone who put up, say 90 points with two great linemates. You could maybe say that latter line is worth 2M more than former line, but that player carrying that former line is probably worth a lot more than anyone on the latter line.
Years ago - starting in 2005-06 there was massive PP time. It was simply ridiculous. But the amount of PP was falling each year thereafter. So if you have a guy who put up great numbers the last two years, but was highly PP based and you sign him to a big contract for the next 6 years, then you are paying for a guy who puts up great numbers on the PP at a time when the PP is becoming less and less of the game.
This is why I am big fan of Matthews. He has shown that he can put up big numbers no matter what. You give him PP time he will put up big numbers. You give him crappy linemates at 5v5 he will put up big numbers. You give him even better linemates at 5v5 he will put up even bigger numbers.
For Nylander that is not the case, but his pay as the secondary figure on a great line is not bad (nor is it great).
For Marner, well I hope I am wrong, but I think people are going to be disappointed. I am not saying that he is going to bad, but I highly doubt he is going to look good enough to justify 4M more than Nylander. People will say that he will continue to naturally progress and he very well might. But it is interesting, when a prospect or player is not progressing we say "development is not linear" but when a player has been progressing well we change to a belief that it is linear. To me last year was a year in which everything that could have gone right for Marner did go right. Yes, he might get more PP next year - although his PP time per game was higher last year than the previous two years - so he might get less. I suspect that they are going to stack a PP unit and play it more because players like Matthews are going to demand it, but I feel it would be better for the team's success to run two different units evenly.
TL: DR - My view is mostly meh.