The IETF process only prohibits normative references to non normative IETF RFCs. It does not prohibit reference to normative W3C standards.
Names arrive at their meaning through usage.
The problem with the URN working group was that they pretty much ensured that their proposal would never achieve any usage. Lack of hierarchy never did much good for gopher URLs as I recall. I remain mystified at by the advantages of making the URN syntax incompatible with the URL syntax. If names are used for a purpose then they have meaning and it is inaccurate to describe them as 'bogus'. Whatever naming scheme anyone comes up with, there will be nothing to stop someone assigning an incompatible semantics to a name.