Worlds and Monsters has pages and pages telling a GM what sort of play points of light will support, how it can be used, how the different fantasy elements - fey, demons, undead etc - can be used to create a fantasy game experience using the "just in time" techniques that 4e's situation-based design works well with.
But for some reason they chose not to include this sort of stuff in the DMG. The DMG has a lot of advice on the metagame of building combat encounters, but almost none on the metagame of building and running a skill challenge (there are general guidelines, but no almost no details at all), of designing and resolving a non-railroaded scenario, etc.