The first thing which the film has in its favour is its title, which is descriptive and to the point. What is this movie about? It's about the Empire striking back at the rebel alliance after its ignominious defeat at the end of Star Wars IV: A New Hope. Conversely, The Phantom Menace was about... um.
In addition, Luke's abilities improve at a believable rate... well, as believable as can be expected, considering we're talking about some sort of mystical power. Luke obviously possesses the "Force" whatever it is, but that doesn't mean that he's able to use it properly after the few lessons that Ben gave him before he let himself be killed (stupid, stupid). Luke has to work and train hard, and we see him fail as often as we see him succeed.
During W.W. II Coventry, England was the target of a devastating bombing attack by the German air force. In later years, it was claimed that an encrypted message about the attack had been intercepted and translated by the cryptoanalysts at Bletchley Park. The claim was that Churchill knew that Coventry was going to be hit, but did nothing to stop it because that would have alerted the Germans that their code had been broken and rendered it useless for the Allies. As it turns out, this wasn't true: they had broken the code, but the message only informed them that there was going to be a strike; it didn't give a location, and Churchill assumed it was probably going to be London again. But if he had known, what would have been the right thing to do- let the attack go on unhindered, sacrificing the lives of the people of Coventry for the greater good? Or preparing for the attack, alerting the Germans that their code was broken, probably resulting in greater loss of life later on? It's something to think about.