Course redesign can be a major undertaking, but utilizing the data derived from your existing course can inform your decisions on what areas need to be targeted. When you combine the four factors I mentioned and use them to form a holistic, summative picture of your course redesign project; you can be certain that what is currently working in your course remains, and what is not working is revised.
Via Nik Peachey
Interesting article on using data to help redesign courses.
Some basic tips and references for a systematic redesign of courses.