The closest I can figure is that the movie is a filmed representation of Kidman's divorce from Tom Cruise. It dawned on me partway through that this could be taken as a metaphor for their relationship — the replaced people standing in for Scientology, Carol's ex-husband standing in for Cruise (epitomized by his telling Carol how she hands out pills to make people feel better, while they just changed people and made them better). She refuses to leave her son while the cult-like pod people close in on her. I am sure this was not their intent whatsoever, but it was funny how it seemed to pop out at me.
This was meant to be Oliver Hirschbiegel's English language debut, but I cannot help but feel it has been marred by outside meddling. This does not feel like the work of the same man that delivered Downfall and Das Experiment. Maybe one day we will get to see the original cut of the film.
Bottom line. Despite all of the ill will I seem to have directed at the film, I cannot deny that I left entertained. Kidman was a lovely presence on the big screen, and Craig was solid in his limited role. There are some creepy scenes which help save it from being a complete wreck. In the end, though, you would probably be better served by one of the earlier interpretations.