I think this review in particular has missed the point of the film entirely. It isn't just pure titillation and the one-central plot point of Lucy becoming a Sleeping Beauty.
While the themes are sexually based, the message is more focused on the objectification of women and how Lucy is so completely unencumbered by her own encounters outside of the job. If you look at it from her point of view, she lives a lifestyle already detrimental to her well-being, and she has no understanding of what goes on when she falls asleep, all she knows is that she gets paid.
This isn't even completely about the men in the film. While there are perverted pigs like the second gentleman we see with Lucy in her sleeping state, we see softer men, like the first who has a soliloquy based on "The thirtieth year". His performance alone puts Lucy's job into question for the viewer. Some men are doing this for their own personal, deeper reasons.
However, the themes do extend to dark areas such as Lucy's indifference to her sexual partner, having her decision made for her by the flip of a coin, and her debilitating drug use.
It's all about context. In any other film, yes, the atmosphere and mood conveyed through the themes would mean condemnation and brandings of pornography or titillation, however there is just, something, about this film, and the obvious depth yet subtle lack of personality to Lucy's character which creates a juxtaposition. The viewer never knows what Lucy is thinking, and her motives remain unclear for the length of the film. However, 2 stars is simply wrong for this movie. If you think it's boring, go and watch an action film.
This is art, clear and unrestricted, and to brand or even review it as anything else is ignorant.