This show isn't for comic book fans alone, just as the Nolan Batman films. It's so anyone can access it.
Nolan took the stories of the comics and reinterpreted them in a way that anyone can access and take seriously, and envision logically in our reality. Arrow is trying to do the same.
If you want straight up adaptions of the comicbook material, that's why Warners has the DTV films. They're specifically for comic book fans.
Laurel having meta-human screaming powers won't really add much to the show. It would just undermine it.
There actually aren't that many super-powered characters within the 'Green Arrow' mythos. Some of the few that do have superpowers can be reinterpreted in realistic ways without losing anything about their characterization. I believe Deathstroke will be handled in this manner.