Since there are standards for ePub I must use all of the required standards whether I particularly use them or not. I do like a description although most eBook readers won't allow me to display it. Some publishers might use it for an online description of the book but most want it separately I believe. I like lots of metadata, in particular the publish date for copyright determination is useful. rights was not listed in your list but is useful for the same purpose. You should really look at our wiki and view the
Dublin Core list of applicable entries. Subject (genre) is also needed but not in your list.
Dale