A world-building script is a script that is heavily reliant on its setting. These are commonly genre scripts, but not always. A script that’s got an esoteric historical setting or relies on a densely woven political backstory has the same strengths, weaknesses and opportunities.
MINORITY REPORT is a sci-fi world building story. Much of the texture and fun of the movie comes from its densely imagined future.
THE WIZARD OF OZ is a fantasy world building story, one full of witches, magic, and flying monkeys.
GAME OF THRONES marries a fantasy world with internecine imagined politics.