The problem: Unknown mime-types are displayed as attachements. People are confused due to these "broken attachements". That is why I do not use "PGP/MIME", for example.
As far as i know, there is no mime-type stuff to the proposed "semantic alternatives".
Is that really an issue? I get those weird attachments from Outlook very often, mostly in corporate mail. I think most people have been conditioned to simply ignore them.
As far as i know, there is no mime-type stuff to the proposed "semantic alternatives".