There's lots of little things I think. Like I have my trackball scroll by holding down middle click and moving the ball. Not too hard to do in X11, works in all window managers too. I have no idea how to do it Wayland, it seems like it's a different process for every compositor/DE. I think maybe I could do it in GNOME but then I'd have to use GNOME.

So far the only positive thing I've noticed about Wayland is that it plays better with my pen tablet but that's also extremely frustrating because why is better pen support linked to the compositor/window manager in the first place. Everything else is either the same or worse.