It should and likely will go to whoever is a major locker room leader and presence both on and off the ice. Someone who is respected by their teammates. I can't imagine contract status will play any role at all, unless the team has already decided they're getting rid of a guy next year or whatever.
The whole "player X isn't worth his contract" thing is something that concerns the fans, but to my knowledge that's not really something the players themselves care about. You might get the odd player who is resentful, but otherwise most players are happy for their fellow guys when they get the big contract.
I have it as a toss up between Kreider and Trouba, based on what I've read about the team's makeup and have observed over the years.