> Um, startup is fast on low-latency connections, sure. Now try it over a higher-latency link.
That example doesn't add points to Wayland because in cases when you actually need that (rare cases, like running Oracle GUI installer on a server without a video card on board) you can still make it work faster under Xorg (vnc, xpra, etc.) but you can't make it work at all under Wayland, since you can't start Wayland compositor there.
> the worst I've ever encountered was over a dialup modem and took more than half an hour to map a window, though admittedly that was a program that took a couple of seconds to map its first window even on Ethernet
Still if it's slow for some programs but fast for others, then those programs are to blame, not Xorg, right?
In that particular case I would try selecting simple widget theme on a server side for that slow program, without nice gradients, cool round buttons or realistic shadows. :)