Entities are extremely useful, to be sure, but don't offer the flexibility of
XPointers by a long margin. The project I'm working on is really a
feasibility study at this point, and that flexibility is key to this
particular project. It could in fact be implemented with entities, but that
would require creating far more files that we have hoped for, as the data we
want to reference comes from different and overlapping portions of a small set
of documents. Implementing this as entities would require far more
maintenance whenever a change came down the pike.
The processing model we'd like to see for EMBED is very similar to that used
for a text entity, but it doesn't look like we'll be getting there soon.
Entities and NOTATIONs serve their purposes, but XML-Link seems far more
flexible, especially for our needs.
Simon St.Laurent
Dynamic HTML: A Primer / XML: A Primer (January) / Cookies (February)