How or to what the XML Schema being added to? If this were to be implemented what would it add the XML schema to? Is the
 schema bound to individual documents or is this expecting a capability to be available in the underlying data resource?

Also the description states that:

" If a schema cannot be associated with the collection because the documents in the collection do not validate against 
the schema, the operation must throw a fault."

This worries me a little. There is an implicit assumption here that every document in a collection has to be validated 
against the schema being described. If I have several thousand documents this could be an expensive operation. In 
section 4.1.2 it states that more than one schema can be associated with a collection  does that mean that all documents
 have to validate against all schema or can a schema be used for a subset of documents. I think this needs to be 
clarified.
.