If the whole PT story wasn't centered around this moment, many fans wouldn't have been so down on it. Lucas's whole reason for the PT was why did Darth Vader turn to the darkside, so logically you are watching the movies figuring it will be some climatic scene that will make 22 years, and 3 more movies worth the wait. Instead it is anti-climatic, and I believe if Anakins turn was more a plot point instead the WHOLE point of the PT, there wouldn't be as much anger as there is towards it. The PT could have essentially been more macro, as the Clone Wars could have been the main story of the 3 movies, and Palpatine seducing Anakin could have been just a plot point along with all the other stuff we waited for to fill in the blanks.

I guess what I am saying is Anakin's turn should have been just as important to the story as Padme starting the rebellion, which was deleted from ROTS, or Yoda/Kenobi learning the force ghost trick. Instead all those plot points were shoveled aside for the new saga title 'The Tragedy of Darth Vader' so of course people are going to expect the turn to be something memorable!