Great post, it brings back a lot of memories. Two additional factors that designers of these APIs consider are:

* GPU virtualization (e.g., the D3D residency APIs), to allow many applications to share GPU resources (e.g., HBM).

* Undefined behavior: how easy is it for applications to accidentally or intentionally take a dependency on undefined behavior? This can make it harder to translate this new API to an even newer API in the future.