I'm not aware of anyone who sees "feature inconsistency" as a feature. The actual feature is extensibility and the cost is inconsistency.
The compliance suites are an attempt to "fix" this as much as is possible in a distributed, anarchical community.
The XSF is working on adding compliance badges so that projects can advertise their level of conformance.
Things however happen slowly because the FOSS XMPP community is small and largely made up of volunteers.