To me Wayland has the problem that too much functionality is done inside it. Basically it does the function of the display manager (X), compositor and window manager. While the last two were usually done by the same component also under X (while not strictly required), having the display manager and the window manager as separate components makes sense.
i thought it was the other way around. in X11 everything including display manager and compositor are part of X itself, only the window manager is a client, whereas wayland separates the protocol and the compositor and display manager. the latter includes the window manager because a window manager always had a privileged position, and that i think interfered with the security architecture. by not having the need to allow a privileged window manager, wayland apps are more secure against interference by other apps.
i thought it was the other way around. in X11 everything including display manager and compositor are part of X itself, only the window manager is a client, whereas wayland separates the protocol and the compositor and display manager. the latter includes the window manager because a window manager always had a privileged position, and that i think interfered with the security architecture. by not having the need to allow a privileged window manager, wayland apps are more secure against interference by other apps.