A lot will depend on the make up of the 48 game schedule. It has been reported that teams will only play within their conference, but it is unknown how much will be divisional play.
If teams play divisional opponents 6 times, that will make up 50% of the season. In that scenario, I could see teams like Pitt, Flyers, NYR having a more difficult time gaining points as they will be trading off with each other. Teams like Carolina and Washington may benefit and achieve higher point totals feeding off Tampa, Florida (who I don't believe will be as successful) and Winnipeg.
As for the Leafs, if they can have winning records against Montreal, Ottawa, and Buffalo and show some level of respectability against the Bruins, which isn't completely out of the question, they could be a playoff team this year.