[Supermancho]

To be clear, I'm implying that a meaningful branch merge commit message is important. That's the change that matters for project history...which may or may not include a squashed history of the branch. The individual commit messages before that are for the developer(s) to manage as they see fit.

At any time, a developer might make another branch, then merge branches or squash the whole history of their branch or create a new branch and add the changes as if it was a fresh branch. Meaningful history is lost in those cases as well. Adding micro-managing process might get (more or less) predictable results, but it almost always pushes developers toward anti-patterns ensuring those predictable results are not what was intended.