Lack of the date of publication in the metadata is but part of a wider problem. The metadata in Calibre does not comply with any standard for bibliographical information such as Dublin Core. This makes Calibre entirely useless for professional cataloguing, e.g. in libraries. In fact, Calibre is great for creating RSS-documents and for format conversion. But as a cataloguing application it is, unfortunately, rather amateurish.
But I do give thumbs-up for adding a field for the publication date. That would be a small step forward at least.
