XML needs:
Enhanced syntactic modeling capabilities for generic XML processing/validation.
- Especially: Means for inheriting multiple vocabularies in XML instances, and for proving that they are all used correctly.
- Note: lexical modeling features, and many other syntactic enhancements can be made to XML by means of vocabularies.
Semantic modeling capabilities that allow us to give names to the emergent properties of XML resources that use vocabularies.
A convention, such as that which exists for XML "Namespaces" today, for pointing to these models from within XML resources, so as to indicate the use of a given vocabulary.