On the other hand, what many people are saying is quite true. For one, there's usually not too big of a point to aim for anything other than the head for maximum damage. Why cripple an enemy when you can kill them with the same hit in a different location? The only way that there would be a point is if an enemy can yield to you to stop fighting if they're too damaged or too crippled, which would be great for getting information out of a certain person. If they run away, shoot them in the legs! But if it was the same "kill or be killed" approach in both Oblivion and Fallout 3, then there would be very little point to the whole system.
Mostly I would want it implemented anyway, since the player would be able to experience the crippling effects as well, which adds another small dimension to dealing with damage other than using restoration, drinking potions, or eating food. Maybe another item like the Doctor's Bag from New Vegas would be one of the only way to heal crippled limbs? Anyway, I think it would be interesting to see what would happen if the PC's arms were crippled when trying to fight. Imagine blocking with a crippled shield arm. The reaction times would end up being way off and even if the block worked you would end up taking a good chunk of damage anyway.
the option is stealth your way out to the next town, if you havent a skilled companion with you nor the skill to cure your wounds.