Tangled is considering to change the data host of few records from PDS to Knot; a headless git server designed to be PDS-like service for git repositories. I think this is one of the cases where current atproto PDS model doesn't fit well even with upcoming permissioned space.

Unsurprisingly, it turns out that the requirements for a data storage layer depend crucially on the design of the client application.

Trying to shoehorn all data storage into a single model is exactly the kind of architectural mistake made by people who have decided that a particular protocol is "cool" or "exciting".

The PDS does what it was designed to do - which stops a long way short of "everything".