I agree - it was a rather stilted performance. But because of her other work, I've also always had the impression that that's the way the role was written. Amidala was a child when suddenly thrust into a position of power and influence, and the way that NP portrayed the role seemed to me to be a child attempting to exert control that she wasn't sure she had, but knew she had to pretend to believe in. It was almost as if every time she said something she was waiting to be corrected, but because she was Queen those corrections never came. So she was almost paralyzed by fear of getting it wrong. As the trilogy progressed (and Amidala matured into her role as Queen) the role seemed to loosen up.Roy Hersh wrote:NP was "wooden" in that role. Whether or not that is how she was asked to perform, who knows? Given her other portrayals on film, I would have to believe that was the case. Regardless, I was not impressed with that work, even though I enjoyed the films overall.
At any rate, NP is clearly capable of better, so if that portrayal wasn't what Lucas wanted he could have asked her to do something different. He apparently didn't, so I lay the blame at his feet.