On the contrary; it is a weakness of current browsers that there
is no way to tell them "Display such-and-such a media type as
text/plain in the main window."
At best, this is a criticizm on current browsers. Moreover, even
current browsers make me happy, since I can tell them "Display
such-and-such a media type as with my faviroite text viewer
(which is not IE 5.0)"
I completely agree -- and this is why I think the ability to fall back to text
for things like DTDs offers no real advantages for any significant group.
Normal users will be confused (and we have ample evidence of this in terms
of complaints to support lines), and experts don't want to send DTDs and similar
things to a dumb text viewer anyhow. They want their favorite programmable
editor, most likely one that is format-savvy for such things. This is certainly
how I have all the browsers I use configured.
Also keep in mind that in some contexts override of plain text viewing with
your own application can't be done. (Again, this is a limitation of current
applications and hence not directly relevant, but it is a much more real
issue than the similar one raised above.)
Ned