The stuff that's not backwards compatible in XWayland is mostly already broken by X compositors anyway and needed to be reimplemented, so that's why there wasn'

The stuff that's not backwards compatible in XWayland is mostly already broken by X compositors anyway and needed to be reimplemented, so that's why there wasn't much incentive to fix that. I've seen some of your comments around and I'm really struggling to figure out what your use case is. "This is only makes a difference for rare events like moving/resizing windows." This is actually wrong, that type of split affects the rendering of every single frame. Also, uncomposited X11 is a bad idea for a number of other reasons, the only reasonable comparison to make there is composited X versus Wayland, which is what all the benchmarks I've seen are aiming for.