I'm just gonna say it: Natalie has freakishly short arms.
Anyways, they modified a lot of movements to compensate for that, throwing off a lot of the traditional Black Swan choreography. I think that, coupled with the already so-so dancing as mentioned by Pterodactyl, was what made her seem so un-balletic. But again, Pterodactyl put it perfectly, the movie was made for entertainment, it's not like she was dancing with the NYCB.
Anyways, they modified a lot of movements to compensate for that, throwing off a lot of the traditional Black Swan choreography. I think that, coupled with the already so-so dancing as mentioned by Pterodactyl, was what made her seem so un-balletic. But again, Pterodactyl put it perfectly, the movie was made for entertainment, it's not like she was dancing with the NYCB.