Edged weapons need more TLC. I had some rules once, somewhere, which I can't find, so let's do some new rules as a follow-up to called shots.
Edged weapons can inflict injuries other than mere hits. Called shots to unarmored locations, as mentioned, will sever limbs, making them permanently unusable. If the head is severed, the victim dies immediately, assuming it functions like a normal creature with a head. Most other wounds to unprotected locations cause deep gashes, which are treated as generic crippling injuries (Move 3 and -1 to attacks until healed.) A wielder of an edged weapon can opt to slash instead, which won't cause crippling injuries, but will leave bleeding wounds.
If a victim survives an attack from an edged weapon, there's still bleeding to contend with. An injured character must make make an adversity roll (based on Con) immediately after a combat; if the roll fails, the character dies from blood loss in 1d6 hours. Bandaging the wounds before the character dies may temporarily stop the bleeding (5+ on 1d6,) but roll again at the beginning of every day if the character continues to be active. Dirty bandages may also cause infection (+5 on 1d6, modified by +/-1 for Con.) A leech has a better chance of stopping bleeding, can sterilize bandages, and can also stitch the wounds closed, which prevents further bleeding checks. Ordinary characters can try to stitch wounds, but combat or vigorous activity can tear the stitches (5+ on 1d6.)
Metal armor prevents cuts and severed limbs for any location that is actually covered, basically turning edged weapons into ordinary blunt weapons. Light (leather) armor is gashed by edged weapons, leaving a vulnerable spot that can be target (AC 5) on a second attack; if successful, an attack to a vulnerable spot is exactly like an attack to an unarmored location.
Piercing weapons are like edged weapons, except that they don't cause permanent loss to arms and legs, although they can pierce the throat, heart or brain (AC 3,) causing instant death. They can also cause permanent loss of an eye.