Re: those predeclared entity refs
I'd suggest following Jon's proposal to drop the five predeclared
entity references, but also to try and work declarations of these (and
perhaps others) into lots of sample XML files as they're made
available, to condition the world into considering those a "standard"
part of an XML DTD. In practice, that sort of thing is almost as good
as having it as part of the language definition.
It also provides an opportunity to puff this great XML feature that
allows you to define new entities, rather than being confined to the