The number of locations where you might want to show or hide a widget can vary significantly — having “Related Posts” widget on all blog entries except on posts that are tagged “twitter” (many); or showing the “About Me” widget only on the front page of a blog (few). However, the combinations are endless.
Therefore, I realized that the most important feature should be the ability to find those groups of locations very fast. So there will be only two ways to sort through the content: (1) search, or (2) choose one of the core locations such as homepage, blog index, all pages/(custom)posts or their indices (archives).
Once you have found and selected the sections, it is only a matter of ordering (or chaining) them according to their “power” — low power locations sink to the bottom and are overwritten by the ones floating above them. This is done via drag-and-drop.
The question is — can you think of a combination of locations that can’t be covered using this approach?