>>150043984
Honestly, the girl they got for Supergirl is right for the role. Sweeney would be ideal as Black Canary. Her glamorous and flirtatious presence is in line with what people would expect from the character. But that's a topic for another thread.
>>150042725
Simple, people love pretty outgoing blondes that like to party. It's a Hollywood archetype. She's the modern "girl next door" version with super powers. Not a hard sell.