BOAC - I agree the direction to go at that time was to the West although later on it was to the East. Actually, AF459 started to divert to the West, but then decided the East way around was better.
I really think that AF447 didn't change that 12° from their planned track until they were very deep into the weather and less than 40 km from where the plane hit the sea. The 12° put them on an almost north track.
As far as what causes the subsequent pitch up event, it is a mystery to me with all of the complexities of the FBW logic and computers.