Her dying via the vapors was hardly the worst sin against her character in RotS. She simply became such an unbelieveable wimp in the whole movie, contrary to her character that was presented in the other two films. Gak, even her wooden affectations as the Queen had her evincing more spunk than she did in the entire final film.

The prequels' greatest flaw was failing to develop likeable characters on the order of Luke, Han and Leia. To then squander what little character they had developed in Padme was among the more egregious errors of Revenge of the Sith.

Bah.