In the section where we define the @Identifier attribute, there's a 
table of mex Dialects and it says what each @Identifier should be.
It includes this line:
http://www.w3.org/2009/09/ws-mex/Dialects/ws-mex-all 	 Not defined 

which doesn't really make sense.  In the previous table where we define
each Dialect URI we have this line:
http://www.w3.org/2009/09/ws-mex/Dialects/ws-mex-all 	 None. [Defined in this specification for use in GetMetadata requests. See 6.2 Get Metadata.] 

Which implies that you won't ever see this Dialect URI on a MetadataSection.
This URI is used just for GetMetadata operations.

Leaving it in the Identifier table could lead some people to think they
can use it (or see it) in a MetadataSection and therefore will cause confusion.

Proposal:
remove this Dialect URI from the Identifier table.