There appears to be an inherent contradiction between worldbuilding for transmedia storytelling and creating the setting for an individual story.
Transmedia worldbuilding should create an expansive universe with numerious characters, settings, significant objects, and events. The more complex the storyworld, the richer the transmedia experience is likely to be and the more room there is for multiple stories set within that storyworld.
On the other hand, story doctor Robert McKee emphasizes the importance of limiting the settings for stories. According to McKee, writers need to impose creative limitations on themselves and the first of these limitations should be settings (see the video clip for more information).
When building a transmedia storyworld, it is important to recognize that what you are creating is not a story but rather, a universe from which various elements will be selected to create multiple stories. As McKee says, when creating a story, the writer must be extremely selective in what will be included.
It would be a mistake to attempt to include the full sweep of a complex storyworld in a single story. Instead, selecting just a few elements to create a tightly focused story is the better approach. Then, if there is still plenty of good material left in the storyworld, you can use it for another story.