The one thing I learned from Prequels to a succesful trilogy, Don't do them! Even if they were done right, I still think they shouldn't be made. Sometimes not knowing every detail is actually better than seeing it on screen. Showing the backstory of many characters has ruined their mystique that many possessed in the OT.

The Emperor, Yoda, Boba Fett and Darth Vader were all ruined in my opinion by fleshing them out. For some fans they like to know everything about those characters, to me, I go by the old saying, "less is more."