Yao has awesome fundamentals when it comes to shooting, he trained that since he was a kid. That said, look at Yao's first few seasons in the league, he had troubles with rotating on defense and positioning (typical big men stuff). Heck even the few last years when he played, he had trouble keeping the ball up high after rebounding and sealing his man when trying to receive an entry pass. It's all about what you work and focused on, especially at an earlier age.
