JvR and Bozak aren't going to change as players at this point. They're skilled, put up points and are a defensive liability. That's just what they are, it won't kill the team to have two players like that but I agree we should look to move on after this year.
As for Gardiner how quickly people forget he was playing like a top pairing defenseman last year and was a beast in the playoffs when it mattered. He's had a slow start and made some questionable plays but he has skills that aren't easily replaced. I wouldn't trade him. The leafs would regret it. You have to take the good with the bad on every player. Borgman has looked good so far, he's gonna make some rookie mistakes it's his first year.