I think that Salman provides a good balance between the two in his performances with Yana. He does stand out as a brilliant dancer, but its not as if Yana is casted on the sidelines while he's dancing. She's also doing something equally brilliant. So, I don't think its right to say that he's hogging all the limelight from her. Obviously if he's on the show then it is because of her.
Yana doesn't speak Hindi, so for him to communicate for her makes sense, so I don't see anything wrong with that. But its also undeniable that a lot of Yana's popularity on the show is because of Salman and his talent.