Roddick suffered from a lot of bad mechanics in his tennis. His takeback for his two hander was sudden and snappy, and as Aggasi said probably too reliant on his left hand. Roddick may have developed a more attacking game and had better net play if he had learned a 1hander, but who's to say.
ATP: Topspin is OP. Devs please nerf.
My Tennis: My serve has too much topspin and my forehand not enough.