I think Lucas should have handed the duty for the prequels off to someone else to be honest. They kind of took the menace out of Vader for me with that transformation scene from Episode 3. And I don't think the fall of Anakin was good enough, I have only watched Ep3 once but I remember feeling underwhelmed by the fall of Anakin, I wanted more.
I would like to clarify though I'm neither a Lucas apologiser or a Prequel hater and I have to say I did enjoy some of the prequels, the Darth Maul fight was, overall, a well paced scene and I liked that.
And also I have to put it out there - I liked the Ewoks!!!:D