I prefer Anakin’s Dark Deeds over the piano. The former sounds more personal (it’s names after a character after all), while the piano, though good, sounds more like something you’d play over a montage at the end of a story. The piano also sounds too sad for what Vader is doing, like it pains him to do it, which it doesn’t.
The lightsaber editing is also good, though I’m wonering if you can add bac Vader saying “the year’s have made you weak,” as a way of clarifying when Ben was weak but ready in episode 4 & weaker/unprepared now.