Rant: dont let your tools substitute for personal knowledge of the domain.
As bad as 2.3.1 is, it's still worlds better than 3. The best thing that can happen is for 3 to be scrapped. The worst part is its model. I worked with it for the purposes of PHIN-LDM, and I've never seen a worse clusterfuck. It made dailywtf look positively logical.
I've written my own HL7 (pre-XML v2.x) message parser and generator in Java for work. I'd really like to not have to touch that code again, if possible. My code is easy enough to understand, but I don't want to have to rewrite it support this non-standard XML.
Just putting XML on the name of something doesn't instantly make it all easier.
HL7-XML is already leaps and bounds ahead of the current spec, even with its obvious inadequacies.