I'm actually loving her, because judging by the first episode, the fact that she's a lesbian black girl is about the least interesting thing about her?
They seem to orient her in the direction of a strong character, who isn't too complacent with the Doctor's ego "why do you run like a penguin with its arse on fire?", but still capable of feeling a sense of wonder. It's a welcome change from Clara, whom I really loved, but by the end she was just written to be a complete enabler to the Doctor.
Also, the writing seems funnier than last year? Judging by one episode. That could make Bill a great companion as well.