Clearly, the Leafs need to both find more goals and prevent goals. The latter has been addressed. The Leafs' horrible team defence will be buoyed by a healthy Mike Komisarek (who is hopefully done trying to earn his contract all in one shift), the addition of Jean-Sebastien Giguere and Dion Phaneuf, the emergence of Carl Gunnarsson* as well as having a healthy Jonas Gustavsson. I don't see any need to add more assets to the back end.
However, the Toronto Maple Leafs need to find goal scorers. After 4 seasons of being in the top 11 in scoring the Leafs' slumped to 25th in 2.56 goals per game. They have one legitimate offensive threat in Phil Kessel and only two players in Tyler Bozak and Nazem Kadri that have a decent-to-good chance of developing into top flight offensive threats.
* PDO-related sophomore slump notwithstanding