That actually already exists. In fact, it's how you're able to graphically admin an XMPP server from any common XMPP client, as the server just presents a different form for each type of operation:
https://xmpp.org/extensions/xep-0004.htmlThus as features are added to a server, it's only a server-side change, meanwhile nothing in the client has to be updated to admin new things, since it's just a basic form syntax to express it.