The open face on a 1hbh at the end of takeback is just a function of grip type and a neutral or very close to neutral wrist position. The more conservative the grip the more open the racquet is. If you have an eastern backhand grip and your wrist is neutral the racquet will be in the position you are referring to. The more extreme the grip the less the racquet will be open at this position.
Haas doesn't have wrist extension at contact. He's one of those 'turn the wrist down to close the racquet face at contact' guys. So effectively haas' wrist is neutral at contact as you can see in the following photo.