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.
It is probably not true today, but it may well have been true in 2010 or so, when Youtube started prioritizing watch time over raw views for the very first time. Back then, let's-plays were the cheapest content to produce in large volume, so the algorithm pushed it hard. And it just so happened that Minecraft released around that time. It's quite possible that Minecraft would not have become the phenomenon that it has become without this lucky coincidence.
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.
[1] https://weirdgloop.org/2021-year-in-review/