Marner at over 8.5M a year is an overpay in terms of what he could bring to this roster. Let's not make the same mistakes Toronto made, with the exact same player to boot.
Yeah I would actually like Marner on this team but not for the money he's definitely going to want (11m+). Anything above that 8.5 you talked about, I'd want that guy to be more of a playoff performer and x-factor than he has ever shown he can be.
I don't think throwing a lot of money blindly at a guy just because he's shown he can put up 90 points in the regular season in a high scoring league is a good idea and that can trickle down to affect the roster if their example set by the highest paid player on the team isn't dynamic enough to tilt the ice in the postseason.
Guys like MacKinnon, McDavid, Pastrnak, Panarin, Eichel, Matthews (he's a playoff ghost, but you can't argue with his high goal totals), Barkov, and I'll admit it, Doughty and Kopitar rightfully deserve their 10m+ AAV contracts because of how much their team's performance runs through their individual ability/impact. Guys like Karlsson (these days), Huberdeau, Marner, and Tavares, not so much.
Marner on this team would be a lot like what Teemu was post 05 era. He'll chip in a fairly high amount of offense in the regular season but you're not going to look to him to drive the team like a true elite superstar, he's not going to be involved much defensively, he's not going to be very involved in the physically demanding aspects of the game, and his offense is going to be stifled in the playoffs. Which was fine in the return of Teemu era because he always took discounts to play for us. I am not comfortable seeing this team throw Marner 10+ million for the next 6-9 years for what that amount of money would actually buy this team. I've never agreed with the notion that just because it's rare for a guy with that kind of talent to be available, you need to do whatever you can to get him and throw all caution to the wind on long term impact of an overpay.