I know Nightwing has yet to appear in a movie as Nightwing and not Robin, But I think Nightwing is a cool character, and I would like him to have his own movie.
I think it could it work with the right cast and director, and the movie shouldn't be about Batman's former apprentice, but just Nightwing, a protector of Gotham city.
Sam Witwer as Nightwing
You may notice him from The Mist, Star Wars force unleashed, or Being Human. I think Sam Witwer is really good actor and would fit this role. I think what would make him the best choice is that I don't think he would play the role like he was Robin, but he would play it like he was Nightwing. He could make you forget the fact that he was Batman protege, and make Nightwing his own character, instead of a supporting character for Batman.
Bryce Dallas Howard as Barbara Gordan
She's a good actress and she looks to part to me, So I don't see why not.
Ron Perlman as Deathstroke
Nighwing needs an enemy that he would hate, Most of us all ready know that Deathstroke caused problems for Robin/Nightwing while he was a Teen Titan. Before the whole DC reeboot, Deathstroke caused problems for Grayson while he was Batman, Grayson even attacked Deathstroke in his hospital bed. Deathstroke is a bad guy that needs to be on the big screen, and he is primarily an enemy of Dick Grayson.
Joaquin Phoenix as Black Mask
He is a great actor, who doesn't get a lot of attention, and I think he would could bring out the best in the role of the Black Mask. Somebody has to be pulling the strings for Deathstroke, and possibly another assassin, somebody like the Black Mask.
Collin Farrell as Deadshot
I like Collin Farrell as an actor and I think he would be perfect for Deadshot,I think adding Deadshot would make the movie more interesting if he is competing with another assassin like Deathstroke, and would make Nightwing's story seem more... interesting,I guess.
Christian Bale as Batman
I wanted to chose somebody else, but I couldn't of anybody else that would make sense. Michael Keaton? He would be more suited for the Bruce Wayne from the Batman Beyond series. George Clooney? I don't think we want to go there. So I have to pick Bale.
What do you guys think?