Another idea I thought would be cool, though I doubt it'd happen with this release, would be to focus on the evolution of all the main characters. I'd include a few segments in a row of each character, with a behind-the-scenes introduction for each character, then show character clips, mainly one for every few years. For example, for Grover, show a season one clip, then something from seasons 2 or 3, then something from the late 1970s, then one or two clips from the 1980s, then a 1990s clip or two, and then a few clips from the last decade. Or with Elmo, begin with a Baby Monster clip, then one of Elmo's season 11 clips (I'd be okay if it's something where he's hardly there, since I'd be surprised if he had any starring roles in season 11), then a "Brian Meehl as Elmo" clip, then a "Richard Hunt as Elmo" clip, then one of Kevin Clash's earliest Elmo clips, then a few 1990s clips, and then somethign from the 2000s.
I wonder if any celebrity clips will be included. No such clips were nominated, and with the focus on main characters it'd be best to avoid celebrities as much as possible (unless that celebrity is Kermit the Frog). And if the set is to include Kermit, I wonder if they'd only include material where Kermit appears alongside other main characters of if they would treat him like a regular and show something with just Kermit (or just Kermit and some minor/one-shot characters).