Perhaps a reissue of the 40th set with an extra disk for the 5 years that passed since its release?
Or worse, doing a reissue with additional segments from the past five years, and removing a few segments to make room. Or just removing some/all of the bonus features. Then again, I wouldn't expect the first disc to be affected, unless they moved the first few seasons on disc 2 to disc 1. And then again, since most of us already have the set, it wouldn't really matter much if they removed any clips from it.
But they probably wouldn't go that far. But if they did rerelease it as a 45th anniversary set and added stuff from seasons 41-45, and had to remove bonus features anyway, it would be great if they added some classic clips to disc 1 as a bonus feature (to make it more of a special edition). Maybe clips with characters not included on the set (like Guy Smiley, Biff and Sully, Sherlock Hemlock, Placido Flamingo...), or some fan favorites and well-known stuff that wasn't included on the set.
I hope that we at least get something for the collectors this year, whether it's Old School Vol. 4 or something more like Best of Sesame Street Spoofs. Last year, the only release we got with material from the 1970s and 1980s was Alphabet Songs, and those were all stuff that had already been released on video (and as I said in my review of that video on The Muppet Mindset, most of the best stuff - not just the best classic clips - had already been released elsewhere). As I've said a few times, there have been quite a few video releases this past year that would have been great opportunities for classic stuff, but didn't. Learning Rocks would have been a great opportunity to release more Little Chrissy and Little Jerry material (or they could have put Count It Higher or Rock & Roll on there as a bonus video), and M is for Mystery would have been a great opportunity to include more Sherlock Hemlock material on DVD (not to mention the animated detective series, and Billy Jo Jive, and Detective Grover), but instead they chose to have those to be releases of full recent episodes, eliminating those chances (but they still could have been included as bonus clips). And Elmo's Super Numbers would have been a good opportunity to release more classic number segments, but it didn't have anything earlier than the 1990s and barely any Muppet inserts (though the main plot is a really good one, most of the inserts are forgettable... But recently I watched it again and found myself enjoying more of the inserts better).
With hardly any classic clips released on video this past year and no classic episodes available on iTunes this past year, I am glad that some fans have recently gotten rare episodes/clips to put on YouTube this past year.