I do not understand how people can live with only a single line for the commit message. For a new feature, I need to provide some details what is added and how it can be used. For a bugfix, a single line is rarely enough to describe the problem, what you changed, and why this change solves the problem.
Writing good commit messages is an essential part of using a version control system with a team. When trying to make the git interface easier, this should not be dumbed down. I would rather expect the tool to provide assistance with the usual format of a short subject and a body for a longer explanation.