I think that often commit messages are unnecessary. I propose that by default a user should be able to commit without a message. I don't think this would be a problem from the UX point of view, because a user could get a lot of information about a change, from the history of the GitHub repository, such as from the time of change, and seeing the diff. I think that making commit messages options wouldn't even be a problem for retro compatibility because the feature would remain still functional for those who would want to use it.
