on BSG, they originally thought Dualla would have a bigger role in the series than she ultimately did. That's just bad luck.
As for 'racial casting', they do try to be as diverse as they can; i.e. the lead male is hispanic Edward James Olmos (don't hispanics now outnumber blacks in the USA or something?....)
either way, YES, people have noticed that; while BSG does try to be "racially diverse" and have not just Europeans, but also prominent hispanics (Adama) and Asians (Grace Park), they don't have many black (African) "prominent" characters. But really, they thought Dualla would be as big as Sharon on the show; that just didn't turn out well.
V,
Why didn't it turn out well? Was it really just bad luck, or maybe if they had taken more of an effort to find a way to write for her, they could.
I think they were trying to move Dualla forward with the marriage to Apollo, but they handled that badly and then just forgot about it. It wasn't bad luck, it was poor writing and lack of effort.