XML has become ubiquitous, and it has become so for many good reasons. But, we can all find many cases of XML overdose as well. I have seen two modules in the same Java application exchanging data by passing complex XML documents, which are then translated into application objects, after going through DOM trees. And, if the developers are any more tool-lovers, they would use JAXB, Castor, and any other technology that's available to move data between XML and Java and vice versa. This all makes the application overly complex for no good reason.
Looking at a piece of raw BPEL code in XML syntax makes me cringe (especially the dataflow aspects). Some claim that, with BPEL, we can write applications without "coding" - we certainly don't need to code in Java when we can do that in XML. :-)
