Good points, but note that I came from the other side: I drafted a concept of how to formulate the strictest schemas that I would like to apply in the applicati

Good points, but note that I came from the other side: I drafted a concept of how to formulate the strictest schemas that I would like to apply in the application. Then I realized that the underlying model resembles much more a graph model than a relational model. I agree that today's graph databases are meant to be used for weaker schemas, I believe that they are conceptually a better fit for strict schemas than relational databases are. But probably we need a third term for those ultra-strict databases. From the "look and feel", this new type would almost certainly look more similar to a graph db than a relational db.