(Let's try to get away from "Re: Comments on Draft RFC, shall we? Our
subject lines have really deteriorated!)
Uuencode implementations also differ widely in their (in)ability to work
in a pipe, which can be a problem if you want to write an implementation
that simply pipes a body through uudecode. That's another way in which
uuencode/uudecode are "non-standard".
I agree that the SYNTAX of a cascaded content-encoding header is not
problematic. The semantics are even pretty clear, too. The
implementation, though more complex than the simple content-encoding
field, is also not beyond most programmers' abilities. What I don't
see, however, is why the cascading is necessary. If it isn't necessary,
the fact that it isn't too terribly complex is irrelevant -- it's still
unnecessary!