Are those the teams that you think got better? How did NYR get better exactly? All they did was lose players. How does subtracting Iginla and Thornton make Boston better exactly? Pittsburgh got better by losing Stempniak, Jokinen, Niskanen, Orpik, and Neal? Please explain. Detroit's biggest off-season move was getting rejected by players left and right. How did they improve? The Flyers downgraded big time by trading Hartnell for Umberger. What else did they do? Nothing?
The Sens may have lost scoring on paper, but replacing Spezza with Chiasson and Legwand is going to change the way they play, not unlike when Columbus traded Nash. I wouldn't bet against them.
I would, however, bet that the majority of the teams you list there got worse.