You have to give credit to Boston for being that much better than the Leafs, but as was mentioned above, the puck possession wasn't as woefully lopsided last night as its been in the past. The Leafs were able to mount some sustained pressure, and they got in on the forecheck better than I've seen them do since they beat Montreal 6-0. It wasn't much but it's more than they ever have in the past eight losses to the Bruins. They played acceptable defensively but still turned the puck over way more than they should if they want to be considered a good team. That said, they were still extremely opportunistic and that won't fly over the long term against anybody, let alone the Bruins.
The Leafs have the offensive talent to be successful with the opportunities that present themselves, but they can't simply rely on unforced errors and expect any kind of sustained success.
If you look at Pittsburgh, for example, they aren't a good defensive team. In fact, they are a bad defensive team. Nothing made that more apparent than last years dreadful playoff performance when Fleury's horrible play didn't cover up for their complete inability to play defence. The reason Pittsburgh is so successful is because they control the puck, and therefore dictate how the opposition is going to play. They generate offence, the Leafs don't. The Leafs simply use their offensive talent to take advantage of mistakes and capitalize. Make no mistake, I think the Leafs are one of the most talented teams in the league, based on pure skill. That said, they don't GENERATE offensive chances, but merely capitalize on mistakes at an alarmingly (for the opposition) high rate. This is not sustainable over the long term, and certainly won't fly in the playoffs.
Basically what I'm saying is, I don't believe the Leafs will make the playoffs this year. They have some of the right pieces, but they still lack the ability to dictate the play, something that those teams of the early 2000s were able to do.