Marner situation is kinda tricky because everyone sees the potential and it's hard to want to give up on it, but after 8 years it's like how much longer can this go on for ?
On 1 hand you have the option of letting this year go by, let JT expire and rebuild around Matthews/Nylander/Marner, and use the JT 11M to round out the roster
On the other hand you can re-tool around Matthews/Nylander and potentially trade Marner to round out the roster and bring back Tavares on a cheap deal or let him go as well and use the 22M free
It's a difficult choice but for me, having seen the last 8 years and how poorly he competes in the playoffs I don't think there's any way he can be a part of this teams future. When one of the "leaders" of the team that wear a letter compete like that, it's a problem.
He just has a poor attitude and has shown now for 8 years that he's afraid to compete and do what it takes to win in the playoffs. He would do better on a team as the #3 or #4 guy, it's in the best interest of both parties to go their separate ways.