Why I DONT want to SEE anakin turn into vader
I really hope that they DONT actually SHOW anakin becoming vader. This is because for somebody watching all six movies all the way through for the first time, it would ruin the cliffhanger ending at the end of "empire strikes back". They would not be as shocked that vader is lukes father unless they were led to believe that vader was actually dooku in episode 3. This would also be a justified reason as to why dooku was introduced as a new character so late into the prequel trilogy.
I always thought that in episode 2, Dooku acted and dressed a lot more like vader than Anakin, so they might imply (but not actually show) that DOOKU becomes vader, and not many non jedi know that anakin is vader. After all, if the whole of the alliance knew that vader was anakin, wouldn't luke have found that out BEFORE episode 5 (or one of his friends would have told him-after all, he did have the same last name and come from the same planet)