Here's how I would've written Luke's last stand on Crait, the rest of the plot notwithstanding: Luke emerges into the open after bidding Leia goodbye, giving her Han's dice, thanking C-3P0 for everything, and sending Rey, Chewie, and R2-D2 a telepathic farewell (Maybe he also could've saved Finn & Rose before after their crash). This is the real Luke, shaven & redressed. Ben orders all guns to aim & fire on him but Luke stops every blast mid-air. Recognizing this much grander scale of Kylo's move from TFA, The Order fears he'll fire back. Luke lowers his raised hand. He then redirects the lasers. Instead of hitting them however, Luke sends the volley to the ground at their feet, the explosions kicking up huge clouds of dust obscuring all AT-AT & ships' vision as they desperately but futilely scan for Luke. With him masking his presence from their technology, Ben orders his subordinates against Hux's protest to bring him down. Descending to the surface, the powerful apprentice uses the Force to single-handedly dissipate all the dust. Luke, lifting the dirt off himself with the Force while brushing his shoulder, comments that he's admittedly impressed by Ben's significant growth in spite of the direction it ultimately took. They then have their verbal exchange as in the film. Ben ignites his saber in a challenge, met by the familiar glow of Luke's green blade. Hux orders everyone to hold fire. A few ships try to head for the cave but Luke focuses and safely temporarily shuts them down, the pilots confused. Think of it like a Force-EMP. Ben takes the opening, attacks, and Luke defends against every blow (Both know the other's style). With age having slowed his agility, he uses the Force to aid in his footwork, dodging, parrying, countering. Feeling toyed with, Ben changes tactics and Force-pushes with all his might in a roar (his eyes almost turning yellow for a moment) but Luke's Force-shield lets him firmly stand his ground, calmly holding his saber forward to center himself. His expression conveys giving slightly more effort/struggle but he avoids losing his balance. With neither combatant having taken a single scratch, Luke has his second exchange with Ben before giving his big iconic speech. Upon him mentioning Han, Ben falters for a moment (still conflicted) before charging in anger at Luke who's deactivated his saber, sensing that the Rebels have escaped. Ben's sword passes through him, miraculously only hitting air! He realizes too late that, just as he'd heard in stories how Obi-Wan became one with the Force long ago upon being struck down by Vader, so too has Luke (in this exact instant, after having finally confronted his failures and found peace). Fading away slower than most Jedi, Luke gives a sincere compassionate smile to his ex-student before saying his final line: "... May the Force be with you... Always..." With that, the legendary Luke Skywalker vanishes to everyone's shock. The Order can't fathom what they've witnessed. Ben picks up his saber & mechanical hand in disbelief, shattering both while shouting in rage. We then see for the first time what becoming one with the Force is like from the other side. Before fully passing on, the spiritual Luke (silent but content in his old Master robes) has one last vision, seeing an almost heavenly ethereal image of his old home on Tatooine. Walking to his late Aunt & Uncle's house, he sits outside. Looking to the horizon of the poetic twin suns setting on his journey (John Williams' theme playing), Luke knows that the Light & Dark will go on but the Force is forever. Closing his eyes, he fades into pure light along with the vision.