Drag and Drop functionality in HBD is tricky because you are setting position and slot in the order. We have thought about some type of graphical interface to handle it and we are currently fleshing it out for the enormous SLB redesign project. In the future, if it works well and the community likes it, we can see if it can be ported to HBD.
Great suggestion, especially for users that maintain all levels of their franchises manually.