I think the League relies completely on "Man of Steel" next year. If it fails LoJ becomes unfeasible. If it succeeds, new DC characters will have to follow the model.
Wonder-Woman can't have her own movie. No comics heroine movie has worked so far, and if she fails in the box office that also would prevent a League's movie. Get Batman and Superman to work and introduce the others in the League's film. Those who win the applause of the public get their solo movies as preparation for League 2. And of the Leaguers, I'd bet the Flash is the one with the most potential, not to mention he traditionally works as plot hook for epic stories. Green Lantern, Wonder-Woman and J'on, unfortunately, will have to be the Hawkeye and Black Widow of a League's movie.
And they should cast a woman who really looks like a beautiful adult female warrior for Wonder-Woman, even if she is not famous. No cute girl-faced actresses. Not that they are bad in their art, but WW must have a Xena-like biotype.