I think one of the main weaknesses in the Dark Crystal is the two main characters (the Gelfings) puppets. They are rather small and can barely move their lips to talk. And any sign of emotion seems out of the question. The second problem (and the larger of the two) is the bad writing and story. The story is never very interesting and has to be told to the audience. The writing is equally lame, with some particularly horrible lines. The result is a movie that is very hard to watch, let alone stay awake during, I hope Henson at least learned a lot from it.
1135 quick reviews and impressions of every movie I've watched since 2002.