In light of the work happening for the OpenGeoMetadata API, I propose that we develop a new metadata schema version. OGM Aardvark is about 5 years old and can continue for the long term as the default GeoBlacklight profile.
However, the API is more flexible and offers the opportunity to develop a schema first and then an application based around it. We might revisit our namespacing decisions (use ogm_ instead of gbl_) for custom fields, implement a more robust way of including multiple links, display relationships of items and collections better, etc.