The fact that an ALPA F/O, an American Airlines test pilot, and an Airbus test pilot could not command 50 percent rudder deflection at a simulated 250kts, when specifically asked to do so, tells you what you need to know regarding the design of the rudder control system for the A300-600. At this speed the rudder system seems only capable of delivering deflection that is all or nothing, when a reversal is required.
Combine this with a pilot who seemed to like to use the rudder during a wake encounter, and you have this accident in a nutshell.