For those who simply want to blame the deceased FO/Captain: had the FO or Captain ever before (the accident) experienced serious encounters behind larger, widebody jets? If so, had either pilot made fast inputs on the rudder pedals as a result? Memories of such encounters might be subjective and vague, but helpful.
Unctuous: even if Airbus Inc. never releases the data which aerospace engineers could analyse, could data on the 767, DC-10 or MD-11 be similar to that for an A-300, even if some components are built by different sub-contractors? Are similar size Boeing or MD rudders designed to be much less sensitive at normal climb/approach speeds?
After the USAir 737 crash years ago near Pittsburgh (PIT), PA, didn't Boeing use wake vortex data from 727s to keep the focus away from rudder actuators and yaw dampers? Incidentally, as an FO many years ago we once had a DC-9 on initial climb-out begin to smoothly yaw from side to side, to a large angle, and totally uncommanded while hand flying. Nobody was in front of us and the early morning air in Knoxville (TYS) was cool and smooth. The Captain selected manual rudder, and the yaw disappeared fairly quickly, as we quickly did the decent and approach checklists (plus a PA to minimize concern among the passengers and FA's) while turning onto a downwind for an immediate return and declaring an emergency with tower. He had already experienced this problem years before that on an MD-80. Luckily, at a much higher speed near 300 knots, the "porkchop" rudder would have limited rudder movement to about one inch, if my memory (jet-lagged since yesterday in Schipol) is correct.
My main emphasis is that after any major incident or accident, any manufacturer will strenuosly put the spotlight on any other factor except the possibility that its own aircraft can have a malfunction or need for extra inspections, will it not? Just imagine the potential loss in revenue, whether the manufacturer's civilian sector has been subsidized through massive tax-payer subsidies or not.
