You can do this in multiple ways. You could (playing the devils
advocate) argue that the IETF should create technical specifications
that can handle the policy of the RIRs. After all, to a large extent
the RIR membership is most likely a better representation of
"end-users" (for some definition of users) than the IETF is.
problem is that the rirs, aside from missing protocol folk, are
also missing router/backbone ops folk. so they get a very narrow
view.
I guess this to some extend varies a bit between the RIRs, but in
general I agree. Still, it's a better representation than vendors
voting on the policy...