We’re much better off letting the market decide on the best standard. Imagine if XML had become the only legal standard for data transfer. Or SAML the only one for authentication. While one single standard is preferable, regulators should give the market time to evaluate which standard is battle proven.
I agree requiring XML could have been a disaster. Still, the law seems to need to require more of we are to more meaningfully achieve interoperability. What's stopping companies from coming up with pathological data formats or generally making the data available but not easily available? Could the law specify some necessary characteristics of the data format? What if there already is a popular standard (http://fhir.org)?
If the standard is open (so that anyone can read the documentation and write a fully capable parser), it really doesn't matter what the standard is exactly.
