I remember several years ago when I was in Disneyland during October. It had been many years since I had seen Walt's original park and I was looking forward to seeing some of the classic attractions that originated there. High on my list was the Haunted Mansion. Unfortunately, they had put the Nightmare before Christmas overlay on it. It was well done, but I was I was disappointed that much of the original atmosphere of the ride that Rolly Crump, Marc Davis and Yale Gracey worked so hard to create was lost in the NBC theming.
This is less of a factor for the bears. Lets face it, the changes to the music, dialog and costumes don't dramatically alter the feel of the attraction. That said, imagine that you could only make one trip to WDW in your life (I know that's a stretch for most readers of this site, but try). If you could experience only one of the 3 CWBJ shows, which would it be? My answer would be the original, and I feel a bit bad for the folks who only got to see one of the overlays. I admit that The overlays were very good, but the original was slightly better.
It would be nice to see the seasonal overlays come to WDW. Nightmare Before Christmas, X-Mas Bear Jamboree' and Ghost Galaxy would be welcomed seasonal additions I'm certain.