At Mental Floss, they have an oral history of the infamous Star Wars Holiday Special:
Ugh, the writers were brought on board because they worked with mimes, that explains what's so very wrong with the Kashyyyk segments.
It sounds like Charles Lippencott of LFL is ultimately who is responsible for it being as bad as it is by picking a unique director from outside the system, one that couldn't handle the type of work that was being done and left partway through. Oddly, his completed scene is arguably the best live-action scene in the special, the Cantina torch song.
Poor Carrie Fisher, she wanted to sing that Life Day song... and she's so bad! I've heard her sing since and luckily she is better, but man... that was the low point of a show made up of low points. At least they cut the singing Luke Skywalker number.
Lucas wrote the Boba Fett animated script, and was the one who decided it should be based it off Moebius' art style! Wow, that's crazy, that alone shows more vision than the prequels.
I wonder if someone else had cut it together might if have been watchable. I doubt that though.