At SGML/XML Asia Pacific 1998, I gave a presentation that responded to
Nelson's article. I argued that parallel markup is indeed a good thing but
largely for different reasons from those that Nelson argued. I then went on
to demonstrate how XPointer could be used to achieve the benefits of
parallel markup.
FWIW, the separation of presentation from structure/content predates both
CSS and Nelson's article by about a quarter of a century.
James