Star Wars is hardly the setting for anything profound about such topics, but then that's precisely the point - that a default character whose gender or race or sexual orientation isn't particularly relevant to the story being told, shouldn't always belong to the dominant gender or race or sexual orientation. Because that's how it works in real life too.

In a historical setting you don't have much choice on these things as they would all have too big an impact on what you can and can't do with your plot. In a contemporary setting, a lot more already - and in a science fiction setting like Star Wars, you can have a character who is black just because, and the story is exactly the same as it would have been if he were white, or Asian. You may have seen some of the recent debates about race in Harry Potter, and Hermione now being played by a black actress in an upcoming play - there's nothing in the books that says she can't be black.

It may come across as heavy-handed in some cases - though hardly here - but such heavy-handed approaches, Bechdel tests, and the like are sadly necessary until they have reached their goal and made themselves obsolete.

Their lack of an original plot can hardly be blamed on their female lead or black sidekick.