EGG are assigned opponent's top defensive guys, so it's understandable that they settle at a lower scoring pace.
For the rest of the top 9 forwards, it's simple: they play passive, perimeter games. Nobody's driving the net.
Plekanec: plays his usual smart perimeter game, but got nobody on his line to create space and/or complete his plays
Gionta: the most overpaid 5'7" glorified checking winger in the NHL today. Because that's all he is now. A defensive forward. He has 0 offense left. His biceps injuries killed his shot, he's still a horrible passer and he gets rid of the puck 90% of the time.
Pacioretty: either his hamstring injury is not fully healed, or he has become a skittish perimeter player. Notice how he stops skating and lets himself glide everytime he's 1-on-1 now. Also avoids going in traffic now.
Bourque: works hard one shift, than invisible the next. Misses tons of chances and whenever he shoots it's deflected by a stick. Doesn't crash the net as often as he should.
Desharnais: STOP TRYING TO GRIND IT OUT WHEN YOU ARE TOSSED AROUND LIKE A PEE-WEE! ****!
Briere: His legs can't keep up anymore. Plus it seems that the concussions screwed up his peripheral vision or something, because he has troubles tracking pucks and players. So he's useless 5-on-5.
I leave Bournival and Prust out of it because the offense isn't their job.
So this is why the Habs' offense is gone. We got 3 midgets who are useless offensively 5-on-5 (Gio, DD, Briere) because they are too easily neutralized. We got 2 big wingers who are scared to go in traffic and crash the net (Bourque, Pacioretty) and we've got one playmaking center with nobody to make plays for (Plekanec).
Almost all combinations of lines have been tried with those guys, so can't really find anything that hasn't been tried before.