Only time will show what the future for XML in the browser holds. Right now, it seems that XML has become the unwanted child that nobody wants to play with, because it seems inept when it comes to creating flashy rotating logos.
p:validate-with-schematron example does not work in Safari/Chrome) and some features are not (or not fully) supported yet (for instance, the
p:http-request implementation is really, really simple and limited). But perhaps the processor is already good enough to be released so that users can play with it, test it – and most importantly, figure out if they can do anything useful with it.
Christmas sounds like a good plan.