Another ineresting question would be how should file metadata (exif etc) play into this.
I think the ideal way would be for file metadata to be a default that is easily overriden - I.e. if there is no author template pull the author info from exif if available (with some syntax available to the user to say there is no author info available even if exif has something)
As someone that had my camera set to totally wrong date for few years, I mistrust EXIF. It is a good default but we should be able to easily overwrite it. In case of my camera, which was still analog back then, I finally noticed wrong date when I took bunch of photographs at my first kid birth and all of them had wrong date and year imprinted directly in the photograph.
