1) Implement other storages. Although databases are a natural part of web applications, a direct storage in files and/or directories may be justified. Also, for most applications the full dataset fits easily in the RAM on modern systems.
2) Keep full history. Or provide for this possibility at least. Adding history features to classic database models becomes cumbersome quickly, but for a simple schema it may be provided directly by the framework. This provides for a great audit log if something went wrong. Probably to be disabled if really unwanted and/or storage size is an issue.
Regarding the different background: Although most people want graph databases if they don't want to enforce a certain schema, my desire is the exact opposite. I want more constraints, data integrity as much as possible. I want more than can be easily reached even in PostgreSQL with user-defined functions, such as constraints across foreign keys. So a separate checker is needed, and I believe graph structure with plain links provide a good, simple base to define a constraints framework upon it.