Hello Kim,
  
> 
> I would argue the role Melbourne IT (generating the zone 
> file) is a very
> minor function of the registry. Essential yes, but minor.

I view the DNS registry as the most essential function, with the WHOIS
registry being secondary.
ie the DNS doesn't function without the zonefile, whereas WHOIS can be down
without major loss.  This is why the com/net/org model uses an integrated
DNS registry and primary nameserver role, but leaves the WHOIS function
distributed amongst registrars.

> 
> The role Melbourne University plays is basically equal to that of all
> five com.au name servers (Melbourne University, RIPE, iiNet, NASA, and
> Connect.com.au).

There is a distinction between the primary nameserver role, and being one of
the secondary nameservers for redundancy.  In this model I am assuming that
the secondaries receive a zonefile update from the primary - though that
doesn't need to the case.  The key issue here is one of maintaining the
integrity of the information, rather than just the availability.  ie an
error in the data on the primary nameserver (or in the data in the DNS
registry), can propagate through to the secondary servers.  If the primary
nameserver is down, the secondary nameservers provide redundancy.

Thus my view is that it is better to manage the primary nameserver and the
DNS registry database (domain names, and nameserver information) together to
ensure the highest reliability and integrity.  I am not aware of too many
models where the primary nameserver and DNS registry are run by separate
organisations.  I agree that many organisations can participate in providing
the secondary nameservers.  Relative to users of course as you point out
they appear equal, as at any point in time, you can direct a DNS query to
any of the nameservers.

There is no "need" for the different functions to be provided by the same
organisation, but I think it is more efficient to have them run by a single
organisation to maintain full control over quality of service.  This has
been a major issue for ".com.au" in recent years.
There is no competition gains from having the functions separate.  Of course
it is important that the right organisation is chosen to operate the
functions together, and that auDA has the ability through the Registry
Licence agreement to have sufficient control over the organisation that
operates the registry.

Probably best to discuss further off-list.  Discussing the relative
importance of things becomes subjective.  My original posting was factual.

Regards,
Bruce