After spending a little time playing with Protégé and realising that you could specify constraints for a particular field in an OWL ontology, I've changed HubMed's RDF output to use multiple repeated dc:creator elements rather than one dc:creator element containing a list of names. This now sits alongside the repeated foaf:maker elements that provide more information about each author.
The problem is that now there's nothing specifying the order of the authors. I've had to explain how this works a few times recently, so here's a summary: in the author list for scientific papers (I don't know if it's the same for papers in other fields), the order in which authors are listed is important. The last author in the list is generally the senior scientist who oversaw the work (penultimate authors may also be senior scientists, but the last one is generally the most important). The first author is always the primary author, who generally wrote the text of the paper and did the main part of the work. Sometimes, though, the author list will have an annotation stating that multiple authors (the first, second and third in the list, say) contributed equally to the work, so are all considered to be primary authors.
The trouble is that these details aren't generally recorded in the metadata provided to/from PubMed. A field was recently added to PubMed's eUtils' eSummary XML output called "LastAuthor", but it's difficult to see what value that adds to the existing list of authors which, being XML and not RDF, already contains ordering. What's really needed is an attribute on each name stating their contribution to the work, eg author-contribution="primary", author-contribution="senior" etc.
Update: Having said all that, I then found the document "Expressing Qualified Dublin Core in RDF/XML" which uses RDF:Bag and RDF:Seq inside dc:creator and dc:contributor. Maybe an ordered list inside dc:creator is the way to go after all. The need for more detailed description of each author's role still stands though.