You need guys that can mix it up but also not be a liability on the ice. Big Buf is a perfect example of this and the type of player I'd like to see Toronto have in their line up.
Physical play can turn the game, anyone remember when Kadri laid those two big hits against Washington last year in one shift during Game 3 of the playoffs? Absolutely turned the game around.
When you constantly pound forwards into the boards when they go deep in the offensive zone you make them think twice. Their effectiveness dwindles if all they're worried about is being crushed.