Sight and hearing represents your detecting abilities. They are more important for a mage or for a survivor than a warrior. Those green/red spots on your minimap appears quicker if you have good sight. Also you can target monsters afar if you have good sight/hearing by scrolling your screen. (They even won't see you. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />)
I also suspect that cut-scenes play from afar if you have high sight/hearing.
However, sight is more important than hearing.
