If Toronto can't get the puck to the outside shooter(Matthews) then that is on them. They are far too talented a group to not figure it out. Tampa Bay continues to get the puck to Stamkos on the outside when he's playing(and not injured) and Washington continues to find Ovechkin on the outside.
By putting Matthews on the outside it forces the team to play a more relaxed box which should open up the middle of the ice for Tavares/Marner/Nylander. Here's the kicker, you can't be stagnant. The Leaf's biggest issue on their powerplay is they allowed teams to keep them to the outside by standing still. Teams ran aggressive penalty kills against Toronto. If Toronto was moving, this would be a dream. Instead they were standing still and it became a nightmare for the PP. Which is why that heavily loaded first PP struggled for good parts of the year. It's like the 4 of them believed the hype that they were going to be unstoppable...And they were out to prove the media wrong.