One thing that might have helped Anakin's turn feel more transitional and less convoluted, would have been the introduction of surreal visions, with open interpretations foreshadowing future events. This has been suggested alot over the years, and could have been used to good effect throughout both ROTS and AOTC.

If these dreams have a Vaderish character within them, or even just a silhouetted warrior, whom anakin constantly attacks, this could become a symbol of his growing madness and fall to darkness.

One thing that was suggested years ago, was a version of ROTS where Anakin remains the hero, where the audience does not turn against him emotionally. I think this could work, and would in spirit float much closer to the OT. There would be no obvious turn to the 'Dark Side'. This concept would be discussed very little in the PT, and all we would know is that Palpatine would be some secret Maverick force user who uses these powers. He would offer to teach Anakin these skills to overcome his enemies, and we would hopefully just think 'thats cool'.

WHAT IF, by the duel with Obi-Wan, Anakin's psychosis is to the point where he projects the dark figure beyond his dreams, and he battle's Obi Wan, believing him to be the Dark Attacker. Obi Wan would be fighting, knowing Anakin has turned, and perhaps some sort of dialogue mid duel, would reveal this as Anakin realises his mistake, and that he has gone too far. 'I NEED these powers!'