Recently on several flights on A321s I noticed that the wings seemed very unstable on finals in moderate wind conditons. It seemed as if the aircraft was finding it difficult to keep the wings level and it frightened the life out of me. I had the same experience on an A330 on finals in calm conditions. Does this have to do with the highly computerized flight controls? How come Boeing planes seem more stable?

In fact, you are observing two types os actions on the controls. One come from the system trying to maintain a track by itself, reacting automaticaly to the wind action. These flight controls inputs are compound with those comming from the pilot that instinctively also reacts to the wind on his airplane. These commands are added and thus you can observe a higher activity on the control surfaces. These is a normal situation on Airbus A320 fly by wire family. As pilotos get more experienced on the controls they learn to let the system react by itself, and after that just make a small correction to return to the original flight path.