My example was taken from a package that tends to “properly document” everything in separate documentation files, rather than in the source code. I don’t really think Python should dictate if and how one document their code based on what base classes they use, and pydoc is still useful with code that has no doc strings.

But if this is to be the way of the future, perhaps a warning in the “What’s New” page might be a good idea. The inspect.getdoc() documentation should probably also have a “Changed in version 3.5” warning.

I guess it would be less automatic, but maybe another option might have been to add an @inherit_docstring decorator, or some explicit way to say a particular API (re)implements an (abstract) API documented elsewhere.