Since Star Wars was acquired by Disney, huge swathes of Expanded Universe material was made non-canon, much to the fury of many fans. However, a trilogy of stories existed that were always non-canon, including Star Wars Infinities. Each of these stories focuses on the films from the original trilogy, but change one important aspect of the plot from each film. The first story showed what would happen if the Death Star wasn’t destroyed in the Battle of Yavin.
The comic book starts off following the A New Hope timeline, showing the attack on the Death Star by the Rebel Alliance over the planet of Yavin. However, unlike in the original series of events, the Death Star isn’t destroyed. While Luke does use the force to guide his missile into the Death Star’s exhaust port, the missile itself malfunctions and doesn’t explode. Consequently, the Death Star isn’t destroyed and the Rebel Alliance is defeated at the Battle of Yavin. Several key Rebel Alliance figures, such as Princess Leia, are captured and Luke and Han are forced to flee from the battleground.
The ghost of Obi-Wan Kenobi tells Luke that he must complete his training with Yoda in the Dagobah system, so Han and Luke head to the planet to visit the Jedi Master. After arriving on Dagobah, Yoda tries to pretend that he isn’t Yoda (like he did in Empire Strikes Back), but Han sees straight through this, claiming that it “takes a conman to know one”. Luke begins his training with Yoda and Han leaves the planet to have his own adventures across the Galaxy.
Time passes, Han returns to Dagobah as Luke finishes his Jedi training with Yoda. The group decides that they’re going to visit Coruscant and try and attack the Empire one final time. This time, however, Yoda decides to accompany Han and Luke. The gang are ‘tractor beamed’ onto the Death Star and Yoda uses his Jedi mindtricks to influence the investigating stormtroopers. Yoda remains on the Death Star while Han and Luke head down to the planet’s surface to try and free Leia from the clutches of the Empire.
Han and Luke arrive at the Emperor’s headquarters and fight against the Emperor’s Royal Guards, who are all equipped with double-sided lightsabers. They reach Leia and try to turn her to the light side, but Leia doesn’t turn easily and begins to duel Luke. Eventually, Luke reveals to Leia that Darth Vader is their father and this helps turn Leia to the light side. The Emperor, as is his style, begins to attack Luke and Leia with force lighting, which the compels Vader to step in and fight the Emperor, giving Luke, Leia, and Han time to escape the clutches of the Emperor.
As the gang are escaping, Yoda appears on a screen behind Palpatine and the two begin to talk. Palpatine suggests that Yoda come down and fight him, to which Yoda says ‘I’m coming down soon’. Yoda then, controlling Grand Moff Tarkin, drives the entirety of the Death Star into the Emperor’s headquarters, killing the Emperor, destroying the Empire, a large area of Coruscant, and presumably thousands of imperial citizens at the same time.
This non-canon Star Wars story clearly shows that, if Yoda were to have sorted himself out earlier, he would have been able to destroy the Empire without sacrificing thousands of lives in the Rebel Alliance.