Ideally, world history should not be driven by the text materials but more personalized by the specific themes that you want to get across to your students. The first year anyone teaches a new course, it is easier to use the text as a crutch. As you do this, stop along the way to challenge perhaps the periodization used or the assumptions the editors make, or the omission of a particular event. In organizing the course, it is easy to fall into a civilizational pattern by examining one area after another. This area studies approach to world history provides depth of various core places though leaves out a study of the periphery and often neglects to show the links between the larger places as well as the pivotal role that places on the periphery have had in world history.
Comparisons allow one to use facts to get at differences and similarities.
With world history it is easy to always make broad generalizations, forever seeing the forest but in the end students will have neither an understanding of the trees, even a few of them, or the ecosystem. Periodization helps to determine what is driving the course. Periodization can be overlapping over time. It can also be different based on the region of study. How one decides to organize time will often determine the breaking points and thus the themes conveyed in a course.