I completely disagree because TESB is absolutely brilliant. The characters are all taken to their lowest point. The Rebels are defeated and scattered, Han and Leia are running for their lives and Luke discovers the ultimate villain is the father he has idolized! You can't get much lower than this and it makes their victory in ROTJ that much sweeter! It's classic storytelling to have your heroes reach their lowest before they ultimately succeed in their goals and TESB achieves this beautifully.