Some ideas for this useful modifier:
1- More performance.
2- Merge all modifiers (FFD 2*2*2, FFD 3*3*3, FFD 4*4*4, FFD(box), FFD(cyl)) in one modifier.
3- Ability to selected control points support by linkedxform modifier like lattice and clusters in Maya.
4- Ability to remove inside control points.
5- Add soft selection for select the control points.
6- Snap supports FFDs control points.
7- Add new default shapes like sphere for FFDs.