The side-by-side view in that article is the key user experience reason to leave. The Fandom wiki sites tend to be slow and covered in ads. I avoid them if possible. I'm glad to see more and more groups take their wikis back.
The Runescape wikis left Fandom a few years ago. The improvement to quality and features has been massive. I'm not sure how much traffic the Minecraft wiki gets, but the Runescape wikis got over a billion page views in 2021 [1]. These are not insignificant losses for Fandom.