Which attribute should be used on biblioentry to identify the type of resource? Possibilities include, but are not limited to: pubwork, role, typeof. I suggest allowing pubwork and expanding the current enumeration list.

Should there be a requirement that contributors (authors, editors, etc.) be grouped in the authorgroup element? Processors can handle either case, so it may be fine to allow both.

Should abbrev be required, and if so, what conventions should be applied to its contents? Currently, the default stylesheets use abbrev to generate inline references and, in some cases, as a label in the bibliography. They use xml:id as a fallback when abbrev is missing. There is enough variety in what different styles require for an inline reference that most implementations will probably need to generate inline references using the author and date information. The question is whether abbrev, if present, should override any generated inline reference or not.

Do the citebiblioid and citerefentry elements belong as direct children of biblioentry, and if so, how would they be used?

Should we use othername for middle name and initials, or leave them as part of firstname? The latter seems most expedient. However, othername could be useful for nicknames.

When a resource is part of another resource, should there be two biblioset elements as children of biblioentry, one for the direct resource and one for the containing resource, or should there be just a biblioset for the containing resource? My suggestion is the latter so that the main biblioentry and its direct children pertain to the resource in question and the containing resource is handled in biblioset.

Is it necessary to restrict pubdate to a particular format, such as xs:date? That may be necessary if the objective is to allow the stylesheets to use full or abbreviated month names or to select how much of a date to use. Since a publication date needs no more detail than YYYY-MM-DD, allowing that plus YYYY-MM and YYYY ought to be enough and be easy enough for writers to use.

Should the child elements of address be required? I’m inclined to recommend them, but not require that they be used, with the understanding that some styles may require the address in a form that doesn’t match a raw text rendering. Most of the time, however, I suspect this won’t be an issue, since most publisher addresses are just city, city+state, or city+country.

What, if any, requirements should there be on the edition element? Simplest would be to just have a number. However, there cases where the edition can be more than that. For example, 50^th anniversary edition or Revised and updated edition. I suggest that if the edition is a number, the style can choose how to render it, and if the edition is text other than a number, the style should take it as written.