XML-Relaional modeling needs to be easier for sources that do not provide an XSD.

The main case for this is REST services. REST services do not have a standard description mechanism like WSDL for SOAP services. The inputs and outputs of the service might be documented in a HTML help page, with sample XML documents, with WADL, etc. Hand modeling is too difficult, so we need to come up with other assists. The solution is probably a mix of new features and documented best practices.

For example:
Add WADL support to the importer.
Document use of a schema from XML tool (like inst2XSD)