Sara Lance is the biggest reason people can't get into Laurel Lance. Sara is too people who watch the Arrow the real Black Canary. These are the reasons why:
Sara's back story rivals Oliver:
Remember Sara was gone 5 years too and it wasn't easy for her. She was saved by Ivo and on that ship for a year and then was thought by Oliver dead again, too find out she was saved by Nyssa al Ghul. Took in and train by the League of Assassins, changing her from that girl that got on a ship with Oliver into the woman she became hard, tough, and a little cold. She also trying to be a better person and deal with what the League has made her do.
Sara's an amazing fighter:
Sara's fighting skills rival Oliver and she is consider even, by some League members as one of the bests. Sara was train by the League of Assassins and also has years of experience, where Laurel would have too catch up and in the process bring down the story alittle. Sara also has traveled the world and has been exposed to many cultures.
Sara is bisexual:
Sara has been in love with both men(Oliver) and women(Nyssa). Their are alot of interesting stories that can be told from this point of view. She would be one the first you see on tv in adaptation of comic book series.
Caity Lotz is just great:
The writers of the show couldn't possible believe that Caity Lotz would be that good. She has great chemistry with Stephen Amell, and the rest of the cast. She's who everybody pictures Black Canary being: strong, tough, and independent. She has a strong presence as Sara and when you she see her you're like, that's the Black Canary.
Sara can lead of own series:
Not since to me the introduction of Xena on Hercules: The Legendary Journeys, has been a strong female character introduced on a male show, where she can go lead her own TV show. Sara has just as many interesting ideas you can use for as you did for Oliver. You can go back to the people she assassinated and how their loved ones might want revenge on her. How she trying and progressing to be a better person, in turn hero, does some this sound familar. More probably than anything she can lead a Birds of Prey series.