There were MANY wasted opportunities in the PT....Dooku's character being only one example (the fact that Lee's talent wasn't used, and that he was killed off and replaced with a coughing CG robot is just insulting). TPM was one big wasted opportunity.....should have been Obi-Wan's story....wasn't. AOTC should have shown Obi and Anakin becoming "good friends" (as mentioned in ANH)......Dooku was a "middle of the road" character, more or less the Boba Fett of the PT...neither good nor bad....but then we get to ROTS and GL basically just wastes him by declaring him a full on bad guy, moments before killing him off....Anakin isn't shown lusting for power.....but only seeking it in his obsessive desire to keep stalking Padme....essentially only turning to the dark side (what should have been more or less the biggest (and most anticipated) climax in cinema history) because he was tricked into believing something that wasn't true (and then doing nothing about it once he realized the truth)...........blah blah blah

Revisited still has to work with the material available to us.....we (most unfortunately) cannot reshoot the entire film......so as much as we can tweak things and make them somewhat different, the base material for such an edit IS still the PT as it exists now.