After discovering tales of brilliance of Adywan's ANH, I found this site. I still have not watched it but am looking forward to it very much. Otherwise I will also be following the ESB progress here.
As far as the prequel Emperor is concerned the problem was not that he looked different, as one might expect from less age, but the fact that he looks fake. He looks plastic with contacts bordering on the absurd. I thought that the CG Yoda was very well done, though I'll always prefer the more tangible puppet version.
On an even more unrelated note...in the ROTS scene in which the Emperor battled Windu, why was the audio so wild? The Emperor's voice sounded overwrought by audio editors. I heard that Ian lost his voice at one point. My suspicion is that they were compensating for that.