Luke Skywalker's role in Return of the Jedi.

Only appearing at the very end of rebuild the Jedi Order. Racked with guilt with what happened between him and Ben Solo, he had become disillusioned with the Jedi cause and wished to do nothing with it until Rey showed up. Even then, Luke was hesitant to help her in any way despite Leia sending the scavenger-turned-Resistance member. He was adamant about turning her away and firm on his ground not to meddle with galactic affairs; even if that meant leaving his own sister in her time of need.

Related: Why Kylo Ren Uses A Crossguard Lightsaber

By this time, Han is dead; killed by his own son on Starkiller Base as he was trying to convince Kylo Ren to leave fallout with Ben Solo.

Mark Hamill as Luke Skywalker on the Millennium Falcon in Star Wars The Last Jedi

ittedly, this bitter and pessimistic version of the character was divisive and is one of the most common criticisms of The Last Jedi. However, Luke’s perspective made sense considering the horrors that he had witnessed. Behind his facade of a cranky, indifferent man was someone who was scared and discouraged. At times, the movie showed this softer and sensitive side of the hero, including when he snuck aboard the Millennium Falcon and grabbed Han's dice. However, seeing him actually mulling what happened to one of his oldest friends via The Last Jedi deleted scene would've made his characterization in the movie stronger. It would've better established that, deep down, he still cared about his family and friends. He never meant to abandon them, but his decision to stay in Ahch-To was rooted in his self-doubt following his failures.

Not seeing Luke, Leia, and Han get together in any sequel trilogy is among the sequel trilogy's biggest missed opportunities. Even when all three characters appeared in Luke's Star Wars: The Last Jedi arc had to significantly change. Given all of this, the least the films could've done was honor the original heroes' relationships by highlighting their bond despite having gone separate ways, such as with Luke's deleted scene. Unfortunately, this sentiment wasn't effectively conveyed in any of the films. 

More: The Last Jedi Revealed Luke's Two Most Powerful Uses Of The Force