Of course they don’t look good, they didn’t have much time to build them from scratch with the limited amount of time George had to pick the ones he wanted from several other designs that were created. On top of all that, the main reason that a lot of them are not that great, is because the amount of screen time that these puppets had, it really didn’t matter to George at the time, he just wanted to finish his trilogy and be done with it. He had to over look the Ewoks, Jabba’s palace characters, as well as all the other stuff he had to do. He wasn’t worried about character D, doesn’t look real enough, or Ree Yees can’t move his three eyes back and forth or up and down.