I'm not so sure the penguins game plan can win in the playoffs. The up tempo, north-south, precision game plan just runs into far too many road bumps in the quicker hockey that is played during the playoffs. Space is taken away, any fumble/miss of a pass means the puck is going the other way.
It's chaos... and the players that the penguins require to execute this system just do not react well to chaos. This team is not made to battle in front of the net at either end of the ice. They don't win physical battles down low, they are built to never get into those battles in the first place - but we know during the playoffs that kind of uncontested puck is a legacy.
While the answer may revolve around personal issues, I still think the core can succeed because they are very talented, but I think the team has to learn to play a closer puck-supporting system where we actually see the forwards on the TV screen when our defense has the puck rather than all 3 of them already moving up ice looking for an in-stride 2 line pass. I thought the biggest differences in games 2-4 vs games 5-6 were the number of times the penguins forwards were in their own end supporting the puck out of the zone. I might have had selective viewing in that case - or perhaps the rangers adjusted, hard to say.