Most of the time, better players prefer heavier shafts because they are not concerned about club head speed. They are looking for more control. It is easy to make a heavier shaft with lower torque values. More material is used to make the shaft heavier and thus it can be used to drive the torque value down. A lower torque value means the club will twist less during the swing.
Less twist equates to a square clubface at impact, therefore more control.
Answering these simple questions can help you find the correct shaft for you or the golfer you are trying to fit.