i is a solved problem. ii remains to be seen. Thus far I've seen little use
made of this facility.
I think (ii) is the $1000 question. A $500 question might be: "Did the
authors of RFC 3023 consider the RFC 2912 mechanism for providing internal
data about XML typed data?" (RFC 2912 isn't mentioned in 3023).
While I suppose that feature lists could be used as a dispatch mechanism,
it isn't intended to be one, and in no way obviates the need for propoer
MIME types so dispatching can be done effectively.
I can imagine many possible reasons (e.g., easy adaptation for current
MIME dispatchers), but would like to know which one the authors found most
compelling.
You'd have to ask them. At the time I was certainly aware of the mechanism, but
I didn't suggest it for the simple reason that I believe it to be completely
inappropriate in the context of what RFC 3023 seeks to do. That doesn't mean it
couldn't be a useful adjunct to RFC 3023, of course.
Ned