I’ve been mulling over how to make Luke’s death less sudden and stupid.
It might be kind of corny but I here’s how I see it playing out:

-Luke comes back from his astral projection thing exhausted. He looks over and sees the ghosts of Yoda, Ben, Anakin. He closes his eyes and vanishes.

It’s a little thing, but I think him looking toward all his deceased mentors as they silently reassure him that he has done what he needs to in this life before he accepts himself into the force would add a lot to the otherwise random death scene.

I would also rotoscope him off the island and have him sitting at the abandoned Lars homestead actually looking into the twin suns instead of just imagining it, his battered x wing in the background (a set up that was never payed off in the movie was showing his x wing in the water).