Yeah, Greg & I talked off line yesterday and he convinced me to keep
them orthogonal. (Unfortunately, this convinced both of us that it was
hopeless to try to say something like "multipart messages can never be
encoded at the top level.")
I can also see the argument for Transport-Byte-Type being orthogonal to
Transport-Encoding, but I'm not yet convinced that Character-Set is
orthogonal to Content-type. What does it mean to have something like
Content-type: G3Fax
Character-set: ISO-646
The two really strike me as hopelessly intertwined, so I'd really like
to put them in the same header field.