Machinbird,
I happen to be intimately familiar with a number of PIO incidents on A3XX aircraft, and there are two factors that have been most important in these:
1. The A3XX sidestick (control) philosophy is not rate but attitude based, i.e. you move the sidestick to the side (and with it a caret on the PFD), and the bus will keep the attitude you demand by pointing that caret. So, for example, you move the caret in the right hand side of the PFD and the bus will maintain an attitude to follow that caret. Unlike an analog system, where you bank the airplane and it will maintain most of the bank on its own while you just keep the bank angle with what's essentially neutral controls.
2. When in direct law (i.e. the proverbial has hit the fan and you're one failure short of MAN PITCH TRIM ONLY), it'll start behaving like an airplane you learnt to fly on... and you're in effect flying a rate based control system, where your inputs have to be given differently.
While I have great respect for the beautiful autoflight systems airbus has developed, this very basic control philosophy is flawed in my opinion and could have been part of what unfolded in the middle of the night over the atlantic, inside a CB. Don't go there. We teach that at basic levels...