Yes and no. I mean you can argue it's a matter of taste but I don't think anyone genuinely likes (for example) having to right click and go through two levels of menu, type a name, press a button, wait for results, and double-click on the correct one, just to rejoin the groupchat they were already in, every time they lose and regain connection. The line between legitimate differences in preferences and genuinely bad design is always fuzzy, but I do think there's such a thing as objectively bad UX, and every XMPP client I ever saw had it.

> Prosody and ejabberd exist. They don't take much hacking to make them very usable - certainly quicker than writing a protocol from scratch.

I can't speak to the servers. Just to the clients.