We have two choices:
a) we can use the same means of expression already provided, and make it
harder to distinguish XSchema namespaces from the namespaces used for the
contents of those XSchemas. It may seem more elegant to those who would like
one and only one way of declaring something.
b) we can use an additional means of expression. This may not seem as
consistent, but brings other advantages, like the ability to provide
documentation about what a namespace is really representing, anyway.
I'm still in the b) camp. I really don't want XSchemas to have to rely on
_any_ PIs; I'm even irritated by the PI needed for the XSchema namespace
itself. PIs are gradually blooming across the XML landscape like hideous
rotten flowers. (Yes, I'm strongly biased against PIs, if you hadn't noticed
already.)
Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer / Cookies