I am trying to work ou where the work being done in MDL-76834 Web service modernisation has got to. It seems that just over half that epic is currently done, mostly in 4.4 and 4.5.
It was announced in this thread "Dependency Injection, and Facades" which as you can tell from the title is not specifically about web services.
However, today, if you go to the main developer docs about web services, there is nothing to say "the recommended new way to write web services is ...". There is specific documentation on the Routes part of this, but that is not enough for someone thinking "how should I implemented a web service".
So, thank to anyone who can clarify this.