Board Thread:General Discussion/@comment-27121579-20151030110310/@comment-4010415-20151114005254

Her spiky hair is still there. It's just way in the back, and you can only see it while her head is turned to the side as she's taking her mask off.

There's also the fact that they admitted they almost ran out of time making Breach. It's reasonable to believe that they had to reuse assets in order to speedily throw together a model for Raven, so they used Yang's hair model, in order to have the front of her hair. They might have also used Yang's face model and slightly altered the eyes to be a slightly different shape than Yang's eyes.