I've stayed away from posting in any and all of the trade threads for Karlsson because I honestly don't know much about the other teams and how much their players are worth. But, the one thing that stays with me during all this is that I don't think Karlsson wants to go anywhere. That being said, I think his hand is being forced because he does not want to play for Melnyk.
I believe if Melnyk would sell, Karlsson would play out his days in Ottawa, as he loves the city, married an Ottawa girl and really doesn't want to be anywhere else. It's possible he doesn't want to sign an extension, because he's hoping that Melnyk will sell. Then it would be a no-brainer for him.
If he doesn't sign an extension, he could help some team this year and come back home to the Sens next year. Or, he could play out this last year of his contract in Ottawa in the hopes that Melnyk will come to his senses and sell the team and he won't need to go anywhere at all.
Maybe I'm living in a dream world.