Recasting Boba Fett and the Emperor for continuity’s sake is a good idea on paper, but both miss the mark completely in execution to the point where I prefer the originals.
It’s really galling when you learn that Temuera Morrison is fully capable of doing a Boba Fett voice closer to Jason Wingreen’s. I’ve heard that Lucas had Morrison record the lines over the phone when it was around 2 AM in New Zealand; I wouldn’t be up for a proper line-reading at that time, either.