I'd really hoped that we would have been able to trade Marner. But we didn't and here we are. For now. There's still a few months before the puck is dropped to start the next season, and things change, and how those changes affect teams that Marner might be willing to move to is something we just have to wait to find out.
On the plus side, I think there are a few considerations that have not been given their due.
*Marner must work hard to change the perception of the type of player he is should he want to ask for the 'accepted' 12M/yr many seem to think is the auto ask. He may be the 7th most productive player the last 5 years, but his playoff production takes a big hit, and if it does this year too, I expect teams to recognize this weakness in his game and offer accordingly. No team wants to overpay a player who wilts during the most important time of the year. Marner has to change that narrative.
*The Berube effect: I think Keefe was put in an almost impossible situation dealing with 3 young highly skilled, highly paid players. As a young coach he had to 'feel' his way into the league, and as the experience increased so too did his asks, but it was apparent that management was less than supportive. Berube will have no such difficulties in establishing the type of play he wants from his players. The consequences of not playing the way he wants will come swiftly. Marner will have to accept this, and I have to think this will improve his on ice performance. The point totals may not be as high, but I believe it will translate to a more well rounded game, and a better player come the playoffs.
*Our improvements on the blue line will help our forwards, perhaps Marner most of all. I suspect his TOI will come down a bit because he won't be PKing as much, but more that he won't be playing as deep in the D zone to support defensemen who have trouble with the puck. He'll be receiving the first outlet pass earlier, allowing him more time to scan the ice and attack with greater confidence knowing a Tanev is there to support. While he has faults, let's not forget Mitch Marner is a darned talented player, and the more time he has to do his thing the better.
Essentially, Marner won't get the big pay raise if he performs in the same fashion he has. He needs to develop that next level of commitment. He's betting on himself and that could be a good thing for the team.
Or, he could poop the sheets. We'll see.