Meaning, if there is a docstring, we will not get the call signature,
we get that only when there is no docstring. Personally I would prefer
the call signature always, like in elisp. Then perhaps when doing C-c
C-f (python-eldoc-at-point) show the (full) docstring. But that would be
another bug-report I guess.
If you think you can program this, the latest ElDoc allows you to do just that. See the docstrings of eldoc-documentation-functions, eldoc-documentation-strategy, eldoc-display-functions and other variables prefixed eldoc-echo-area. Also see the new interactive command M-x eldoc.
All of those things have been touched recently by me, and I'd appreciate the feedback.
João
João