No question that Boober and TM were clearly designed for Goelz's 100% "gonzo" delivery of an oddball character's line--Gorgon Heap said:What?! That's crazy talk. IMO Dave Goelz's World's Oldest Fraggle was brilliant, as were Boober and Traveling Matt. Muppety greatness from a creative standpoint, and Muppety brilliance from an acting standpoint. Boober's vocabulary, TM's ego, WOF's abusiveness & condescension- great stuff that Dave was great doing.
But was thinking more along the lines of Jim Henson not wanting to play a permanent role in the series (among other things), but still writing in a few guest-character shots for Cantus and Convincin' John once or twice a season...
WOF was only designed for the "Finger of Light" episode, and only caught on later once Juhl, Stevenson & Co. caught the established-canon bug.