maybe after dooku is out of the way, the emperor manipluates anakins/vaders mind creating the most fearful paranoia that Padme had betrayed his loyalty and trust with Obi Wan, thus knowing Anakin's anger would get the better of him and make him go back after Obi Wan only to find Padme, and then we see him strike her down, that would be a pretty dark ending showing the truest and darkest moment, But again would be contradictory to Return Of The Jedi, where it shoes his weakness for his son, bu there again, perhaps his love for his son is unconditional where as the love for his wife, is not.
Actually I hope this isnt the ending come to hink of it.... It would probally scare the sh*t out of the little new generation SW fans that Lucas films has created and slow down the rate of purchases on Anankin And vader dolls and memrobillia!!!