Of course there is, because Marner is a premier player.
Dispense with the idea that Toronto is hamstrung because of optics, because what has been speculated already is that teams - plural - are interested. One reporter with a stellar reputation believes the number will greatly exceed a list put forth by Marner IF he (and his agent) agree.
McDavid, Draisaitl, Mackinnon, Panarin, Matthews and Pastrnak are the only players who have scored more than Marner in the last five years.
He's not overpaid. He's underperforming in the playoffs certainly, but you can say the same about Tavares and to an extent Matthews himself. The argument is there that it's a problem with composition and support. Marner is not THE reason Toronto hasn't advanced past the first round with regularity.
What is germane in any speculation is this: Marner is simply the easiest of the four to move given his impending contract status, age, production, etc.
The expectation in Toronto prior to Nylander's contract was that his worth in trade talks started with a number one defenseman in return. I prefer Nylander (I'm on record on the Leafs boards) to Marner, but I don't look at Marner the player with diminished value so much as misplaced value in Toronto.
And if you were familiar with the player's past, his value as a point-producer, and avoided recency bias for the plague it is, you wouldn't be so quick to dismiss Marner for Dunn.
And as for overpaid rental, again, whether its just a general unfamiliarity with how these things work, if Marner and his agent get that list of teams and it's narrowed down, the idea is to sign with that team; All of the details will be worked out. Marner's valuation is a known quantity and there are clubs out there who have the space.
He's not going to be traded as a rental.
And as for wanting to trade Marner, again, context: If Toronto wasn't bound by cap, if we could spend our way to a properly structured defence and any number of reasonable ifs, its unlikely Mitch Marner would be bandied about in rumour mills.
There's Toronto's structural needs, but then there's the need for franchises across the league to obtain one of the top ten best point producing players in the league, playoffs warts and all.