In to-day's NHL, it will take only one more "top 20" forward to get the Leafs into the playoffs. Don't forget they lost about 15 games by only one goal. A "top 20" forward is the difference between winning by one goal and losing by one goal. In the unlikely event they can land a "top 5" forward the Leafs can easily be a top 5 team.
As much as I want the Leafs to be a legitimate contender, a top five forward will get them into the playoffs, but it will take a bit more to put them into the top five teams in the East.

