Are you implying we need to be able to change the Primary Key?!? Never. You even mention a dislike for natural attributes as primary keys. Of course. Because natural attributes can change and primary keys should not. Changing a primary key breaks the relational aspect of a RDMS.
With the primary key fixed, any other value (attribute) of the set (a.k.a., record) can, and should be allowed to change. Every table in every database I create has a minimum of 3 columns: Primary Key, Create Date, Modified Date. I expect the data to change. But, the Primary Key will never change.
It seems to me the problem is not the database, it's the application that uses the database. It's not a DBA's problem. It's an Application Developer's problem. They failed to properly gather requirements. They, apparently, only coded the happy path.