The transition to Wayland also seems to correlate with the adoption of client side decorations (CSD). This "modern" approach destroys the traditional UX of XFCE as seen by recent changes in the settings manager. I fear for the future of XFCE. The advantage of XFCE for me has always been that it's a stable implementation of a traditional Win98/XP UX. I hope they don't adopt more Gnome3 patterns.
CSD has nothing to do with UX. CSD just means the application draws the window controls and borders.
Sure it does. Allowing windows to draw their own decorations, often in different ways and with different styles and themes, and not respecting the settings in xfwm4 as to what window-control buttons should be drawn (and where)... that's a huge UX issue.