If the only reason that he'd be getting moved from Vancouver is because he doesn't want to be there because they're not competitive, why would he be ok with being traded to a team that was worse than them this past season?
From what I read it was more than just "being competitive". That's clearly part of it but he stated (paraphrasing) "I want to see the direction the team is going in." Vancouver hasn't had a direction in years, in fact, they remind me a lot of the JR/Karmanos Canes years (only giving out worse contracts). Trading 1st round picks for OEL (and now Hronek), Signing Myers to a terrible contract. Sign JT Miller to a long term deal, but let Horvat go. etc.... They are a team in limbo with no apparent direction. Not to mention being on their 3rd coach in the 5 years Pettersson has been there.
Hamilton went to the 3rd worst team (NJ) in the NHL, and two season's later they are one of the best
Faulk went to the best team in the NHL and a few season's later, they weren't even a playoff team.
Karlsson wanted to go to a contender so he went to SJ. They made it to the WCF that year and haven't been to the playoffs since and were one of the worst teams in the NHL.
My point is that what we think of as "contenders" or "bad teams" today, may not be the case in a couple of years. Things change quickly. Detroit isn't there, but I do think they are headed in the right direction. Pettersson would make them a playoff team IMO (goaltending is questionable, but so was NJs). They have a lot of young assets to make a move as well.
Anyhow, it was just a guess on my part, not one that I feel that strongly about, but above was my rationale for making that guess. The good news for Carolina is that we have a team that should be able to be competitive for a long time, especially with Aho now signed long term, so that will be attractive.