Theres a clear negative tone across other NHL franchises towards the Leafs and Leafs players. It doesnt happen with every fanbase and in some cases they could be right about certain things, but to say it doesnt exist and even on this very site would be hilarious.
Even if you want to discredit other parts of his game (he was actually good defensively this season), he's still scored goals just about as good as anyone else when you factor in oppurtunity and thats immensely value considering scoring goals is the hardest thing to do.
Malkin is a phemonial player no doubt but noone even knows what Matthews will develop into. He is still a guy that can use his size more often and develop a mean streak (Joe Thornton didnt until later in his career). We just saw the unreal leap Mackinnon made from ages 22-25 and it wouldnt suprise me if something similar happened with Matthews.
His under usage early in his career cant be talked about enough when thinking about what his offensive ceiling is.