A lot of people argue the player composition argue from the angle of us not being big and tough enough. I myself don't see it, I think the Leafs win a decent amount of 50/50 puck battles but some people just expect us to win every puck battle, they're called "50/50" battles for a reason. In the defensive zone, it's not so much that our guys lose the battles on the boards, it's that they're never good with their positioning. And as far as our puck movement goes with the stretch passes, it can look like a complete mess at times.
Defensive zone play is not about perfection though. Now that Muzzin's here are he's made a few noticeable f***-ups, I think people are realizing that the grass isn't always greener on the side. Even the best make shameful mistakes. Adding Wayne Simmonds and Gudas won't have much of a noticeable effect on the team IMO, these types of guys will make their own mistakes as well and the toughness they allegedly should bring is overstated IMO.
The team composition is totally fine IMO. We have two elite #1C's, two elite #1RW's, a decent #1D and a decent #2D with the acquisition of Muzzin along with one of the best goalies in the league. We fit the bill totally fine, in fact, when we do a player-for-player comparison around the league, extremely few teams can match us, and we have a legit case for being the best team on paper. In sheer talent, the core is unquestionably elite and our supporting cast is most definitely above average. We are long past the days of having Kadri/Bozak as our top-6 C's and Phaneuf/Gunnarsson as our top pairing.