What we want
From MARC must die!
Non-library specific solutions
Libraries are a relatively small sector with limited means of innovation. We should make sure we are learning from the best, and not just muddling around in our own little stagnant backwater of a much bigger pond.
All kinds of "entities" described in librarie's metadata should have identifiers that make it possible to explore the relationships they are involved in with other entities in the metadata.
This is strongly related to identifiers. If we have good identifiers we can make it possible to connect metadata from different sources and make it possible for users to explore relationships between entities in novel and interesting ways.