If our biggest problem has been scoring goals and our top guns are unable to carry the load, that's an argument for needing better depth. The big4 experiment, which for the record I loved every minute of, has not delivered and comes at a very direct cost (40m) of meaning our 3rd and 4th lines are manned by a rotating cast of guys who don't score in the playoffs. Hasn't mattered if they're big and strong, small and skilled, fast or crafty, none of them since Kapanen have scored when it matters. If we're keeping Nylander, that means we're extending him, and I am not excited about another decade with no depth, built around the same core with the same weaknesses. We don't NEED to trade Nylander, but I'm at the point where I'm willing to talk about it.
Muzzin has been one of our most important players in the playoffs every year he's worn a Leafs uniform. I very strongly believe that without his impact, we will have a new big problem. None of our other defensemen bring the presence that he brings, and they can't do it by committee.
Ultimately, I have zero doubt that
@Fogelhund is right and that this year will just play out with the pieces we do have.