This cut has pros and cons. I agree that it makes Obi-Wan’s abandonment of Anakin more believable. It places the reveal of Vader onto RO, imo the shadow is far more epic.

At the same time, you’d be losing arguably the best performance in the trilogy. Also, how does Obi-Wan get Anakin’s light saber? If you recolored the lightsaber red for Mustafar you could write it off as a new one but if it’s blue that might be seen as a plot hole. Lastly, this cut makes Anakin’s defeat purely misfortune, instead of his recklessness causing his burns.

Both this and the original have their pros and cons. Personally I prefer the original, though this is a cool alternate take that could still work.