You should definitely squash away fixes to commits that are part of the same commit series you're submitting; you don't want to submit a broken patch followed by a second patch to fix that broken patch.

But as part of your point that commits should be the "minimum necessary change", it makes sense to send a logical series of patches that iteratively change a project to implement a new feature (e.g. adding new infrastructure), rather than one big patch to implement that feature.