Here's the problem as I see it. Seabrook is a "leader" on this team. This is always the argument people bring up when scratching him is discussed. He wears a letter. He is supposed to be an example for the young guys. One time in the playoffs he said something to Toews when he was losing his cool. He also scored some big goals many years ago. So, sure, he WAS one of this team's leaders.
But, every player, at some point in their career, reaches a point where they can no longer effectively "lead", because of their on-ice performance. How can he be vocal and hold the younger players accountable when he is one of the absolute worst players on the team? It would be one thing if he appeared to be going 110%, selling out to block shots, standing up for teammates, etc. But most of the time, he's not even moving his feet out there. If he's talking, he's likely being tuned out by most of the guys at this point.
I think if JC really wants to take control of this team, and instill accountability and work ethic into the room, he absolutely has to sit Seabrook. How can a guy be a leader on a team when his best, 100% effort(if it even is), is what most guys are doing when half-assing it? What motivation do the young players have to play harder, when they see him out there stinking up the place every night, and continuing to be thrown out on the PP and PK? How can you hold the young guys accountable and change their approach to the game if you aren't holding everyone accountable?
Joe Thornton is a hall of famer, and even he had his C stripped away for a better option. At some point, it needs to happen. I would sit Seabs, and the next game, his A would be on Shaw's jersey. Yeah, yeah, Kane. Maybe Kane is an option if it sparks him and he starts playing some semblance of a 200 foot game, but I don't think that's going to happen. You sit him for 4-5 games in a row, and when he comes back you just keep the A on Shaw's jersey. Shaw is a heart and soul guy, is a two-time cup winner, is 28, stands up for his teammates, and I guarantee nobody is questioning his work ethic or his desire to win if he steps up and talks.
If Seabrook doesn't start seeing regular press box duty this season, I'm on the fire everyone train. He's a detriment to the team, and at some point, guys will start resenting him because of his play, and it will end up fracturing the locker room. You need to start handing the reigns over to the younger guys at some point in the retool/rebuild, so it can be THEIR team. I would start that process with moving an A off of a guy that should be in the press box 75% of the season.