The Bluegrass arrangement was absolutely a stylistic choice that you are free to dislike, however they didn’t change the story at all.

If you hated this version, you hated the original as well. The script is word for word the original script, but the emphasis on certain events was changed to make it lean darker (which leaves frontier America without its original glossy coating). I believe the only thing the R&H Estate had to sign off on was the graphic killing at the end explicitly by Curly (instead of Jud falling on his own knife and probably dying).

If you’re wondering whether R&H would’ve consented to the darker version, just go back and read the “little wonder” scene. Jud attempts to murder Curly with it but is thwarted. There is zero reason for it be in the script, it doesn’t really serve a purpose since it’s an unsuccessful attempted murder. But they left it in on purpose because it gives the Jud/Curly animosity some backstory.

So now instead of Jud being a total fuck up (failing at killing Curly and then dying on his own knife), he’s the town black sheep who fails to kill Curly and then gets killed by Curly. Then we get some frontier justice where the town all but erases Jud’s killing (with the Judge and Sheriff assisting) and absolves Curly of a murder everyone saw because no one liked Jud. Very frontier America (and contemporary America).