Half of Jedi is turning the pride of the Empire, the Storm Troopers, into a gaggle of half-wits who cannot defeat a small army of Ewoks who have far less advanced technology.
It totally destroys the idea that the Empire should ever have been considered a threat, and negates the idea of technological advantage meaning anything at all.
Also, their second Death Star was literally half built, with massive parts of it missing or broken. The Emperor, instead of waiting for it to be completed, leaked the information about where it was. Even if his plan is successful and he wipes out the Rebel Fleet, one fucking lucky shot at a half built Star Destroy fucks up everything.
Yeah you could argue that his plan was full of his arrogance, something Luke mentions, but it flies in the face of the cold calculating man he is/was in the prequels.
Jedi is not a good film, and beyond the confrontation of Luke, Vader, and Sidious, it is one of the worst Star Wars films.
