There are two possible routes:
1. Provide access to the ChildPositionComparator. Pro: You can sort any combination of pages. Con: Will only work with Page specifically, and doesn't necessarily make sense outside the context of the specific set of children of a single page. Users can only reorder pages of a single child, using that ordering when mixing with other hierarchies will be potentially quite confusing.
2. Add access to the 'getSortedChildren()' method of a single Page. This will probably be the route to go down, since it makes the most sense...