1. Add @from and @to to each biblScope that is a page range to show a good way of making page ranges more explicit so that people aren't tempted to use type="fpage" and type="lpage" (which is especially important in page ranges where initial digits of the end of the range are omitted).
2. Change "Punctuation should not appear between the elements within a structured bibliographic entry encoded with biblStruct or biblFull" to "Punctuation must not appear between the elements within a structured bibliographic entry encoded with biblStruct or biblFull"
3. In "Des Minnesangs Frühling" example, change <date when="1977"/> to <date>1977</date>. While there are good reasons why you might do dates in a highly structured bibliography not encoded from a source document, the rest of this citation appears to be of an encoded source document, so it's misleading to use this markup in such an unexpected way.