Actually, reStructuredText as well as the style guide from PEP8 apply mostly for coding the Python's standard library itself, albeit a lot of third party programmers conform to that as well.
I agree with you that the Google's style for arguments is much better from an in-code perspective. But you should be able to generate such docstring with sphinx as well, with the new lines and indentation preserved. It doesn't output as nice as with a more sphinxy formatting though.
Anyway, you don't have to use sphinx, and by the way, the autodoc
module of sphinx is definitely just a small part of it. You can virtually use any documentation generator which is capable of retrieving the content of docstrings, like Epydoc (which support epytext as well as reStructuredText, Javadoc or Plaintext) or pydoctor, or even a more universal one like Doxygen.
But definitely, sphinx is quite pythonic, very convenient to use with Python, and make your code consistent with the Python's ecosystem. I think you are not the only one who think this is a "lack". Maybe they will take these complaints into account in the future, or maybe you might even consider modyfying the autodoc
module by yourself, should not be very difficult, it's in Python, it would be a good exercise.