I think a thing JR didn't get enough credit for is how he was able to consistently add young talent to the team, even though their prospect pool stunk. JR constantly added guys like Kapanen, McCann, Marino, Pettersson and such to the NHL team and got significant contributions out of young players. Hextall actively traded away young players on their roster and Dubas hasn't added any young players either.
I have a feeling that this team would still be a playoff team had JR never left, probably not a great one but still a playoff team. He would have found out ways to add young talent to the NHL team, even if the deals would have been stupid.