It would be nice to have an option for setting the author date in the commit UI (basically support git commit --date).
I think it's useful e. g. for cases where you commit work you've actually done the previous day, so that the dates in the commit history carry useful information. I could imagine it being implemented as a field in the UI next to the commit button, that per default just says "Date: now", but gives you a date picker when you click it.