If a field like "Author" is completely missing, set to "empty" or set to "Unknown", we should probably give that a bit of a more descript representation in the UI of MMV.
Especially Unknown is quite confusing, since "Unknown" without the label of "Author" looks quite stupid.
Uhh... template parsing is bad enough, adding natural language parsing to it is really something I would rather avoid. Eventually all this will be handled by Wikidata which has a proper "unknown" value.
One way this could be handled were to leave the author field empty (the approximate date of when the work was created does not belong there), make the author metadata markup only appear when the field is non-empty, make "Unknown" the default text, and add some fallback text for a missing author in the viewer (we might have done this already).
This would also make the file page more readable for non-English readers.