XSLT 2.0 - One namespace URI, two collections of names

I apologise if this issue has already been raised on list. I have a vague 
recollection of seeing some discussion of this issue but don't recall where.

In the Namespaces in XML Recommendation the following definition is given: 
"An XML namespace is a collection of names, identified by a URI reference".

In XSLT 1.0 we have the namespace URI http://www.w3.org/1999/XSL/Transform 
associated with the collection of element type names enumerated in the XSLT 
1.0 Recommendation.

In XSLT 2.0 we have the same namespace URI associated with a non-identical 
collection of element type names.

So, on the surface at least, XSLT (2.0) is not consistent with the Namespaces 
in XML Recommendation.

I appreciate that an XSLT processor will, in all likelihood, use the 
xsl:version attribute to resolve the ambiguity. However, it seems to me that 
succeeding versions of many XML application languages are likely to provide 
successive distinct collections of element type names, associated apparently 
with the same namespace URI.

Perhaps this is an issue for the TAG, rather than being an issue specific to 
XSLT 2.0.

Andrew Watt