I would like to see the Page Query be able to reference a property of the layout outside Data Driven Pages. This would let a user set a property on the layout and pass that along to the query property of a layer or layers. This would allow for a single map to power several layouts having layers query different features in the different layouts without having to duplicate the map and change the query in the copy. The function can be partially duplicated by using Data Driven Pages and using the Page Query based on that but you cannot have different layouts for each pages or customize extent beyond a few settings.
