I see no reason to have news use a different solution than e-mail.
It only creates unnecessary complications for gateways.
Well, basically it is the same, but with some improvements and
enhancements. MIME should be enhanced in the same way, to remedy
the inconveniciences found in 2 years of MIME practice.
If you can get consensus in the IETF that MIME should be modified as
you suggest, I have no problem with the same extensions being added to
netnews.
But I suspect that, barring unfixable technical flaws in RFC 1522,
any change at this point would cause more inconvenience than it
would alleviate.
Keith