In Star Wars Return of the Jedi, George Lucas and his team discussed the early treatment of the story and its characters, namely, Luke Skywalker. A good debate transcript from 1981-82 reveals Geroge Lucas’ response to Lawrence Kasdan when proposed to kill Luke Skywalker in Return of the Jedi.
George has an eloquent way of discussing the matter as to why he feels that would not be the best thing at all. We also get a glimpse into an alternate ending to Return of the Jedi with Vader’s cape getting stuck during the Death Star countdown, after Palpatine dies. This is when we see Luke taking Vader’s mask, putting it on, and saying «‘Now I am Darth Vader.'» Kasdan was in favor of that ending, but it’s ridiculous in my opinion and I’m very happy George Lucas went with the ending that we got from 1983.
Do you think George Lucas has the same outlook on Luke Skywalker dying in The Last Jedi? I would assume so, as he had treatments for the sequels and none of the variations we’ve heard of had Luke dying. In fact, quite opposite. Luke was a power house, and defended the galaxy with the help of his sister.