Should an aircraft be affected whilst flying an approach (at an airspeed above Vmd) which results in a reduced airspeed -i.e a sudden tailwind- the aircraft will have a reudced airspeed. The reduction in airspeed will result in a loss of lift and a reduction of drag. With reduced total drag and no change in thrust the airspeed returns to that orignally flown by the pilot and equilibrium is restored. No restoring force or design features are required.
Below Vmd, drag in the same situation and the reduction in airspeed will result in an increase in total drag. Further reduction in airspeed result in an further increases in drag. Only then, is pilot intervention required.