The backing hook of a halberd may be used to trip or forcibly dismount a mounted opponent; a spetum or ranseur is well suited to disarming an opponent; the beard of an axe may hook around the top of a shield and may be used to pull the opponent off balance or to expose their centerline to attack (lowers armor class).
Will P:E allow us to take advantage of these and other secondary weapon functions? I certainly hope so as this will move combat beyond a very basic "hack 'n' slash" level.