I don't know what you saw last year against the Bruins, but I saw a team that gave up after Game 2. Sure they tried harder in 3 and 4, but they knew they were done. The Bruins were a concrete ceiling the Pens kept bumping their heads against. The fact that the Bruins then lost to a team very similar to the Pens should have caused a bit more soul searching among top Pens brass and GM Ray Shero in particular.
Only after the series did it come out that Chara had punched Crosby in his recently healed jaw, a cheap shot made worse because Bergeron had Crosby in a bear hug. Apparently this happened in Game 1. Couple that with the Pens deflating 6-1 loss in Game 2, in which there were NO fighting majors as the Pens got embarrassed at home, made even worse by the cumulative score of the first 2 games, and you have a team that lost to the Bruins not because of a 2-3 zone defense, but because they were scared of the Big Bad Bruins.
Ask yourself why Brendan Morrow didn't take flight and bury himself in Chara's chest, or why Iginla didn't run over Tuuka Rask, or why Doug Murray didn't break Milan Lucic in half. These players were unable, or worse, unwilling to play outside the lines in a way that Bruins were comfortable doing. Was it because they were pending UFAs, was it because they were forbidden by Pens coaches? Or was it because they didn't really feel like their teammates were worth it?
With all three gone, who is left to grind opponents down? Matt D'agostini? Jussi Jokinen? When Evgeni Malkin is the Pens biggest forward, there are problems.
The Pens thought they had the tools for a long, grinding, physical playoff run last year and they got punked. Now all three "tough" guys are gone, and the Pens are destined for an early exit or a regular season where their smallish players are ground into dust by January.