Did Breaking Dawn Part 2 disappoint expectations?

Now that filming the Twilight series is complete, and Breaking Dawn Part 2 has been shown in the cinema it is available to buy on DVD. I assume it is no longer a spoiler to discuss elements of the film and plot. 

As I watched the movie in the cinema I developed the strong urge to compare it to the book. The feel was different to me. In the book series, I felt that the stand off between the Volturi and the Cullens hinged around the strength of Bella's ability as a "shield". That is her ability to block psychic attacks of all types.

In the movie the drama appeared to revolve around a vision shared between Alice Cullen and Aro. The audience was taken through a battle where Aro killed Carlyle and eventually lost his own life. When the point came where Alice pulled back and revealed that the entire battle we had just watched had not been real, members of the audience gasped. There may have been a general feeling that a good percentage of the picture was a ruse - a deception - a waste of emotional time. 

The change was described by reviewer John Boone as a "big twist" designed to make the story more cinematic, as everyone got to watch Alice's projection rather than mere frustration as Jane battered against Bella's guard.

(See http://au.eonline.com/news/364003/breaking-dawn-part-2-s-big-twist-everything-you-need-to-know).

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