In the OPC UA core specification, it is a pain that the stable base that must bei implemented in stacks and core libraries is in the same namespace than additional optional application level features. This makes it difficult to separate implementations for the core functionality from "loadable" extensions needed based on product requirements.

I can see two aspects in FX that would hava a similar issue.

One is all types needed for base automation component functionality, expecially connection establishement related functionality. I assume this will be stable after initial development and will be implemented in base OPC UA stacks. It would make it much easier to provide this base implementation independent of the application specific features if the related types would be in their own base namespace.

The second one would be all types related to the connection manager. Since a connection manager is not implemented by all FX applications, it would be much easier to skip this functionality if it would be in its own namespace.