I wish Johnny Quick was still around since he really stood out from the Flash's. These days where DC complains the speedsters are too similar he wouldn't have that problem.
For one thing he isn't named the Flash. His costume is very different. He uses the formula. I like how Waid used this to contrast him when the other speedsters were all for the more mystical speed force.
He also has the superhero family dynamic being married to Liberty Bell and the father of Jesse Quick. Also I think he was able to fly at one point.
A lot of different, interesting aspects to explore of his that other speedsters don't have.