Reorganize sub-task order within the parent task

Currently, sub-tasks are ordered in the parent view by creation time, and can be moved up or down in the list by clicking on the arrows. When lists of sub-tasks becomes long, it is quite tedious to reorganize, especially when adding new higher priority sub-tasks (they start at the bottom of the list).

It would be nice to have a feature that allows sub-tasks to be inserted at a desired position in the list, and possibly a number of sub-tasks to be moved/inserted as a bulk operation.