I think it's a combination of things. The primary one in my mind is the injuries carolina has sustained recently...ray whitney reinjured his groin against tampa bay and will be out, glen wesley practiced for the first time but won't be on the roster tonight, Rod Brindamour is out, Nick Wallin is out, and andrew hutchinson another defenseman is also out. As you can see they are pretty battered right now.
Throw on top of it the revenge angle as you said w/ the canes beating them twice this season.
Ottawa outplayed carolina in the last game but the canes were fortunate to get some good goaltending out of gerber. He is the reason they have continued to win recently, but you can't overlook the losses to tampa and atlana where they were dominated.
The only play here if any is Ottawa but i won't lay that kind of chalk so it's no play for me.
Good luck fellas.
