

Looking evil isn’t a limitation, it’s flavour text. It doesn’t affect the story, it just gives us vibes. If there’s one thing Rowling is good at, it’s writing flavour text to convey vibes. But there’s no plot in that limitation. Horcruxes break Sanderson’s second law, and that’s why they’re not as interesting as the One Ring. The One Ring puts challenges in front of every character who interacts with it: Sauron, Isildur, Elrond, Bilbo, Gandalf, Frodo, Gollum, Galadriel, even Samwise. It promises all of them something they want, and takes a price from every one, changing the course of the story many times. Samwise is the least affected, but it still takes away something he loves; his best friend.
Horcruxes do four things: they kill Dumbledore, give Harry a quest, make Ron grumpy, and ex machina the deus. Bringing Voldy back and manifesting Riddle don’t count because those are retcons, and we’re talking about writing processes.
Two of those things they do are just because they’re a macguffin. Literally anything the characters want could have been substituted. Ron grumpy is, again, flavour text. The Deus ex Machina is the one interesting thing they do to change the story.
It also corrupts Isildur, makes Bilbo grumpy, gives us insight into Galadriel, creates tension between Frodo, Sam, and Gollum, gives Gollum multiple personalities, starts an argument at Rivendell, makes Gandalf fuck off for a decade, gives us insight into the strengths of hobbits, weakens Frodo, drives the epilogue, creates the ringwraiths, and contextualises the stagnancy of the elves.