I don't think there is a point in getting it complete. You choose the XEPs you want by looking at what your client/server goals are. Also if you need help in choosing, there are pointer XEPs, like the Compliance Suites, or the mailing list, or the chatrooms. See https://xmpp.org/community/
> Getting it 'right' seems to be a problem when the XEP definition is open to interpretation.
When in doubt, ask the author/council.