Just a shower thought…
Can Obi’s:
“Then my friend is truly dead. Goodbye, Darth.”Be edited to:
“My friend is not dead. Goodbye, Darth”This can help to explain why Obi leaves and does not kill him. It will also explain Vader’s line of “Obi-Wan once thought as you do” in ROTJ.
Too bad we can’t have tie fighters launching from the Star Destroying and arriving just as Obi-Wan is about to kill Vader. Reinforcements arriving could provide a reason that Obi-Wan needs to leave. We see tie fighters or the grand inquisitor approaching through the clouds. Something like this:
Or what about recoloring the “apocalypse now” tie fighter sunset approach from the Force Awakens to look like a moon, rather than a Sun?
https://i.pinimg.com/originals/ca/5f/02/ca5f024f484ca8d63cd01b31588185b6.jpg