I have a modern one with a mouse-event bug specific to Wayland, that still presents in XWayland windows. Switched to KDE/X11 just to work around it (so, not exactly enthused to see this news item on HN).

Nope. Off the top of my head, I've had serious issues (crashing, visual glitching, extreme lag, etc) running OpenMW and Minecraft on XWayland, both of which were resolved entirely by switching to X11. There have been many others too, those are just at the front of my mind because they were the most recent.

Oh, also Godot has a lot of issues on Wayland at the moment, specifically the Godot editor. I spent a long time trying to figure those out, because if I'm developing I would really rather be in a Wayland session where my DPI stuff works much better, but ultimately I resigned to just running the Godot editor only under an X11 session.