I love the music in all three videos, but the third one still bothers me because of Ben’s refusal to kill Vader. But,
I believe I’ve managed to galaxy brain a solution of “why doesn’t Ben just kill Vader” that doesn’t involve Reva.

Delete Ben saying “then my friend is truly dead,” & replace it with the end of Ben & Anakin’s duel from “AotC” where Obi-Wan is trying to impart a lesson. While Ben still disappointingly says “Good bye, Darth” to distance himself, deep down he still thinks Anakin is in there. This plays very well with the way the edit is currently is, with Vader refusing to kill Ben in Part III because “the years have made you weak,” & that’s unsatisfying for Vader.

So now, at the end of the edit, Vader & Ben’s relationship has developed into something more complicated & co-dependent. Vader won’t kill Ben because he wants to fight him at his best, & Ben won’t kill Vader because, whether or not he knows it, he still considers Vader his friend, & wants him to grow & gain the wisdom that Ben knows he’s capable of learning.

At the very least, it’s a better justification than “because the Canon says so.”