My thought is more that I would die too often, but it would also make enemies that you fight one on one far easier (but you don't get that too often). Also, it'd be harder to make enemies of varying difficulty if they all die from one hit.
I'm not about one-hitters, what so ever. But locational damage? Absolutely. X2 multipliers for the head, various body parts doing various things when damaged, armor with a point, etc.
Look at my previous post in the discussion about armor deflection with a chance ratio.
EDIT: Quoting my previous post about armor deflection: (This, to a degree. Though it would be difficult to build a "hit box" around the armor, it is absolutely possible. If your arms are exposed... Well, they're exposed and they're a fine target. Crippling should be instigated through damage to the joints, not the limbs themselves. Oh man, I'm sorry guys... But an arrow in the knee is a lot more damaging than an arrow to the thigh.
Armor would be the biggest variable to a successful headshot/crippling shot. Fur and leather could possibly have a 50/50 chance of penetration. Steel, iron or the other "hard" armors could use a 80/20 chance of successful penetration. 80% of the time, the arrow may hit at such an angle that a metallic helmet could easily deflect it.
The biggest difficulty would be balancing that with the armors themselves. Locational crippling by a successful hit is a must, but the armors should respectively follow the same 50/50 paradigm for soft armors and the 80/20 paradigm for hardened armors.
EDIT: Unfortunately, clothes or robes would offer no protection against penetration and would be entirely for the roleplay value.
EDIT2: Perhaps a thigh/leg shot could slow you down for 5 seconds, or a shoulder/arm shot could slow down bow draw speed and weapon swing speed.
EDIT3: A successful joint shot would end in a crippling blow outright.
Haha, EDIT4: How about if you get clubbed in the head it could blur your vision for 5 seconds too? That'd cause a realistic amount of disorrientation.)