A set of merge requests were opened that would effectively drop X.Org (X11) session support for the GNOME desktop and once that code is removed making it a Wayland-only desktop environment.
Going along with Fedora 40 looking to disable the GNOME X11 session support (and also making KDE Plasma 6 Wayland-only for Fedora), upstream GNOME is evaluating the prospect of disabling and then removing their X11 session support.
Some concerns were raised already how this could impact downstream desktops like Budgie and Pantheon that haven't yet fully transitioned over to Wayland. In any event we'll see where the discussions lead but it's sure looking like 2024 will be the year that GNOME goes Wayland-only.
Mine's mostly just bad electron app support for native Wayland. In theory Electron now offers full Wayland support but hooooo boy is it going to be a while until all of the electron garbage I use finally updates to a new enough version for proper support.
The other gotcha is just general client side decorations support for apps in general. I'm shocked that no one has built a small libadwaita wrapper library that implements client side decorations for apps. It's going to be ages until app developers all implement their own (crummy) CSD that doesn't match system themes at all.
You can still use XWayland though, it's not going anywhere. They are only removing the ability to run a X11-only session.
Yeah, fair - they're not so much showstoppers as persistent irritations.
There's this