I would have liked to see a version of Sauron winning - or at least any personality instead of plain ultimate evil in him.
But that is a different story.
So it's the choice between a Drama, Comedy, Tragedy, Romance ...etc.
For me (My own opinion) I can divide movies (and games) between good endings and bad endings. (Good guys win vs Bad Guys win). The ending does not determine if the movie is good or bad, but it does determine if I want to see a movie.
Generally I like movies with good endings. Bringing this back to Adult VNs.
I like games with "Good" endings, meaning I want the MC of the game to have a good ending. Generally, that means I do not like NTR games ("Bad endings")
Having said that. I love a "hero story", where bad things happen during the course of the story, and the "hero" needs to overcome obstacles and sometimes lose while in the middle of the story. That is why I don't call the MC's LI having sex with someone during the game NTR. It's either cheating or just part of the obstacle that the MC needs to overcome (Win the girl)
That is why I avoid horror and tragedy genres. I just want my happy ending. Even if it's bittersweet (like Forest Gump).
TLDR; The version where Saurin wins, is not a movie that I'm interested in. LOTR is about the battle between good and evil and personally, I want good to win over evil. The battle over evil should be hard fought, with some losses along the way, but in the end, good needs to triumph.