> With incompatible \specials, some expertise is needed to even be able to
> exchange TeX source.

It's not so bad most of the time, If I have a document that goes


then I can have a hyperlinked, coloured document which will work
unchanged (at the TeX level)

with xdvi (hyperlinked, but monocrome)
Y&Y's dviwindo previewer
Y&Y's dvipsone/distiller/acrobat
OzTeX previewer
and probably other things as well.

There are still problems relating to graphics inclusion, but that is
more to do with differing functionality than with differing syntax.
If one driver supports including, say, wmf (MS Windows) files, and
another does not, then moving a document that includes such a graphic
will involve a bit of effort and conversion, I don't see how a
standardised \special syntax for that would help much. It would help
me to maintain color/graphics and it would help Sebastian to maintain
hyperref, but as long as somebody has put in the work to support a
given \special set, it does not make much difference to the end user.