First things first: I really enjoyed the movie. Do I think its great? No. But I actually thought the ongoing ballet metaphor (and all the discipline and equilibrium that is involved in classical training) was powerful in showing the development of an "unbalanced" psyche that is trying desperately to cling on to whatever "normal" it can construct. Although certainly repetitive I thought it was inspired,, rather than boring. I also appreciated the non-preachy nature of most of the film, thus I rated it how I rated it.
Having now read some of the reviews, I do understand possible objections to the depiction of the characters transition, and how it is shown. But, as in other instances with many other films for many different reasons, I don't know enough to judge. I will be more aware in the future, so for me both film and reviews were very useful.