Playing devil's advocate:

One of the benefits touted for Relational Database Model at its introduction was that the keys could be based on data as opposed the pointers used in the Hierarcical and Network Database Models. As these database models are much faster than the Relational Database Model, shouldn't we consider using the Hierarcical or Network Database Model? After all the Object Databases that are so new and exciting are Hierarcical or Network Databases wrapped in new terminology.