Despite WBs pullout, the movie has not been officially canceled. If the movie continues to be worked on, it is expected that John Stevenson would still be the director, but it would require a change in director and maybe other lineup. As Film Junk put it:

The move from Warner was expected though since they recently decided to devote more of their time towards DC Comics and their respective properties, which meant that other projects of the same nature would most likely get dropped. Mattel, however, hasn’t given up on the movie just yet and director John Stevenson (who directed the horrid animated feature Kung Fu Panda) is expected to remain with the project which they are actively searching to get set up elsewhere.

We will report on new developments as news about them surface.