Something else that makes me feel very uneasy about the current draft is
the way it defines what constitutes a valid IDN in terms of algorithms
described in two separate documents. This feels to me like putting the
cart before the horse: I think this (i.e. what constitutes a valid IDN) is
a fundamental idea which needs a crisp, easily understood description so
that (for example) any future developments to embed IDNs directly into DNS
don't get lumbered with legacy ACE code simply to determine what is a valid
actually for the sake of backward compatibility it will probably be
necessary to restrict "native" IDNs to the set that than be encoded in ACE.
so defining valid IDNs in terms of ACE actually makes some sense.