I must say that in all of my time working with the TEI's structure of bibliographic description, including working on the Technical Council from 2010 to 2013 on a close editing of various parts of the Guidelines dealing with bibliographic description, I have never known the Guidelines to claim that <biblStruct> is meant for a description of a bibliographic work whereas <bibl> is meant for an instance of that work. There's even an example in section 3.11.1 that combines a <biblStruct> and two <bibl>s in a single <listBibl>, and I don't see any indication that this is a type/token or FRBR-like distinction.
Have I misunderstood you here? If not, I think we need a SourceForge ticket here to propose revisions to the Guidelines to clarify the semantics of <biblStruct> and <bibl>.
On 10/16/14 10:55 AM, Lou Burnard wrote:
[I]f you really want to put a full bibliographic description inside an
individual <msItem>, you can do so, but you must use <bibl>, not
<biblStruct>. This is because <biblStruct> is meant to be used for an
abstract bibliographic description -- a work rather than an instance of
a work -- and has a much more rigorous structure as a result. Whereas
<bibl> is more general. Some people will tell you that <bibl> is always
a better choice than <biblStruct> for that reason!