You can't have a big "masked" vader sequence in ROTS. I was thinking about this the other day. I travel pretty widely on the net and you are the first person I've seen complain but the lack of Vader time. The climax of the film is the Obi/Ani battle, nothing can top that. You've known for the best part of 25+ years what the outcome of that battle is. Any extra screen time of Vader would have taken the shine off the Mustafar battle and thrown the pacing of the film. Anyway, what was left for him to do in that immediate time frame? Destroy the Temple? check Kill Jedi? check Kill the seperatists? check Stop the war? check At this point in time, Palps is the one who is doing all the work, Vader has just pulled himself together again after a tough day at the office. Stop being picky an look at the pacing of the film. I want more Aayla time but you don't see me complaining about it.