I think it's all about location and big history. If Qc comes back, rivalry will ensue very quickly.
The Flyers also played the bullying card like the Bruins, we also played them in the POs, you even had Richards whining in media about PK, but it never became a rivalry.
Agreed that the Nerdiques would be an instant-rival. The Flyers were a rival, though briefly. I remember that Richards interview -- still can't stand the guy because of it. The thing with Philly is the hate evaporated as quickly as their Cup window. Pronger was injured and gone shortly after that season, a year later Richards and Carter were traded, Humongous-Big was brought into play goalie, and we watched as the entire team crumbled under the weight of Holmgren's hubris. Kind of like the Bruins, as a legit rival the Flyers went from Darth Vader to Squidward.