I remember Arias saying that his main goal was to get the ball to the forehand volley when playing Ivanisevic, because you can draw some freebies. If he felt that Goran had the a shakey forehand volley, I can only imagine what he would say about Roddick and Agassi's.
Goran wasn't exactly a great volleyer. I wouldn't even call him good either. He just came into net A LOT...which is something you're supposed to do when you have a great serve like that. His serve created so many weak returns that I suppose making a lot of putaway volleys classifies him as a great volleyer (according to some in this thread). There are tons of "baseliners" who I would consider as better volleyers than Goran.