If the people organizing MuppetFest at Creation and Henson ask Sesame Workshop to participate, well, then we might get Sesame Street included. Personally, I'd love to see a panel or two on SST. It is a huge part of the Muppets and should be represented.
Foam does not last forever. That is why Muppets get remade from time to time. Ever have an old couch or chair cushion? Over time the foam just crumbles away. Thus, the Fraggles need to be remade. Luke is right, we were told Sprocket was at MuppetFest last year, but we did not see him. After MuppetFest, when I brought this up on the forum, someone posted-- quite insistantly-- that despite what we were told, Sprocket is not in working order. Don't remember who said it, but I think we have to acknowledge the possiblity that Sprocket may not be in any better shape than the rest of the folks from Fraggle Rock. But that doesn't mean we can't have a Fraggle Panel.
Luke, the poseable Muppet dolls used for photography (the parody calendars and so forth) were on display in the Henson Museum at the last MuppetFest. They were roped off and, originally, we were not allowed to photograph them. I would love to see photo ops with Muppets, but Henson may not want all our greasy little hands on their very expensive dolls. Can't really blame them for that. All you need is one person with an uncapped ink pen and you have a disaster. Still, I hope they work something out!