1. The women tend to hold onto proper technique. Not that the men do not have great technique, but they alter it according to how they like to play, etc. With the western and semi-western grip, the open stance has come into play and it is the choice of nearly all of the men players. Many of the women still step into the court or into the ball and close their stance off which is the more traditional way. Both work well, but the open stance is better in my opinion as it allows the weight to stay back until the swing and it takes less time to set up for as you don't have to be in perfect position and has the one less step (you don't have to step into the court like the traditional "step into the ball" stroke".
2. The wrist should never slap at the ball. It should release into the ball. Watch Gael Monfils or Federer hit their forehand. It will make sense to you then. Youtube them.