While both of these would be good things to ask for, I don’t think any of them have a place in an ideal Open Data Law.
Adopting the IODC is a political matter that requires commitment from authorities. As such, it makes more sense to be in an executive decision document (such as a presidential or legislative Decree) than in the law itself. For example, in Brazil, that was the case when founding the Open Government Partnership, which was established in the federal executive branch by a Decree.
Technical best practices, such as those recommended by the W3C, have a place in technical documents and norms, not in law. The DWBP, specifically, is quite good at what it proposes (documenting techincal best practices). However, the open data community shouldn’t blindingly accept any output by the W3C, as those can sometimes be aligned in promoting agendas that are antithetical to the “open” movement, as seen recently with its recommendation of Encrypted Media Extensions, a DRM mechanism pushed forward by giant companies such as Google, Microsoft and Netflix. So we should be always wary and critical of such proposals. For example, I particularly find that the Tabular Data Package standard, promoted by the Frictionless Data initiative within Open Knowledge International, to be of much more practical use than the W3C’s CSV on the Web, as discussed here.
Anyway, I digress. Technical standards are in constant evolution and law is something difficult and slow to change. I see no place for technical standards in top level legislation, be it about open data or otherwise.