After mulling over it some more, my view this film inches even more towards disappointment. The main crux for me all comes down to Luke and Kylo’s past. Okay so, Vader has tortured Leia, has blown up Leia’s home planet, has killed many of his fellow Rebel friends, has tortured Han and sent to Jabba’s, has sliced Luke’s hand off, etc. Vader has done some really horrible and twisted deeds, and Luke’s idealism never faltered, even when he was being electrocuted by the Emperor. "Father please!"
Luke’s unwavering determination and faith in his father to have the capacity to turn to the light was what finally convinced Vader to overthrow his master.
NOW…
An older, supposed wiser, Luke wants to murder his nephew in his sleep because he ‘felt’ some darkness in Kylo’s mind?? This isn’t even some random padawaan; his own family! Leia’s and Han’s! How the hell was he going to rationalize this act of murder to them?? Not without lying you couldn’t! I’m not even convinced or shown how Kylo was an issue in Luke’s academy prior to scary Luke the executioner shows up at Kylo’s bedside.
Regarding Luke… we’ve all had 30+ years since ROTJ to imagine what might have happened to the character, and with Star Wars being a fairy tale the default position naturally tends to be “lives happily ever after”.
Remember we are shown three versions of events, the night the Jedi school was destroyed. “Scary Luke” at the bedside is Kylo’s version of events… it’s not until the 3rd showing that we see the actual version of events. And that fleeting moment of doubt, where Luke saw the terrible dark side and thought to strike it down is presented as Luke’s great failure. He feels shame. He IS acting out of character - that is the whole point.
This has beautiful symmetry with Obi Wan. Both Obi Wan and Luke are living as hermits after a perceived failure (“I thought I could teach him as well as Yoda, I was wrong…”).
Luke does get to be a hero one last time, as does old Ben. In their final acts both stand against the might of the enemy to create a distraction so their friends can escape, Kenobi in the Death Star hangar and Luke at the gate of the mountain, and both sacrifice themselves in that moment.
I think Luke’s return - and character - in The Last Jedi, is perfect.