Realistically, the Bruins current stats are very extreme. Marchand and Pastrnak are not going to each score 80 goals, and guys like DeBrusk are not going to put up goose eggs all year.
The Bruins were a real one line team until they added Coyle and Johanssen last year. In the regular season it was enough to beat the bad teams, but it was very obvious that it wasn't enough against good teams.
I think a god line and defense can get you playoff $$$. Heck its been the Bruins model since I was a kid when they just told Neely and Bourque to do all the scoring an everyone else try to win 0-0... but the teams are too good the further you get in the playoffs to just rely on one line.