> A good fix (which is the only acceptable fix in open-source software), is one that speaks for itself.

I disagree. Often if I'm making a PR to an open-source project I'm doing so because I have a use-case that the original author hadn't considered. So the first step in getting the PR merged is explaining my point of view and convincing the maintainer that my use-case is valid. Only when this is done can the "goodness" of the patch be evaluated.