If Cristina Yang Were The Main Character Of “Grey’s Anatomy”

I don't know. She's important for a lot of reasons but I'm conflicted on her depiction. 

I've always felt that Yang was the "sassy black woman" of the show. Go back 20-30 years and you'll find a media world that was nearly all white with the few black people in the space playing something akin to the Yang role. Spicy. Confrontational. Magical knowledgeable friend. 

Is she a person or a caricature? Was it OK then? Is it OK now? True diversity means complex characters that can look like anything.