is rdfs:domain useful as currently defined?

As we've been studying the uses of the RDF Schema vocabulary for
reasoning about models described in RDF, we've come to realize
that the defined 'domain' property is not particularly useful
for inferencing:

http://www.w3.org/TR/2000/CR-rdf-schema-20000327/#s3.1.4

 "If there is more than one domain property, the constrained
  property can be used with instances of <em>any</em> of the classes"

Since we are working in a non-closed world, we can never know whether
we have all the possible domain statements that might apply to a
property so we can never compute a definitive list of the possible
classes of the subject of a statement with this property as predicate.

At best, the domain property we've defined permits determination
that no known constraints have been violated.  This is what the
Working Group intended as far as I can tell, largely at my own
recommendation.  But I'm having second thoughts.

I haven't had a chance to examine other implementation work in
detail to see how people have used rdfs:domain.  At a minimum,
it might be appropriate to change its name so that it is more
clearly distinguished from rdfs:range which *does* allow inferencing.