At a cursory glance through the documents, there seems to be a few refinements on version 0.3:
- Resource map metadata is now (IMO) handled better
- The inclusion of resource typing into the aggregation data model
- Yeah, wonder where they got that idea ;) But seriously, it suggests to type the objects at a conceptual level. I would have liked to see inclusion of more physical typing alongside this, such as metadata standard adherence (dcterms:conformsTo) and a 'mimetype' of some sort (dc:format but this is open to debate).
- Proxies are more fleshed out (I still think that this is a solution looking for a problem though)