One thing about fallout 3 i like was the blowing limbs off, but it only happened on a killing blow. Possibly in skyrim incorperate that while your enemy is alive fighting you and you have high weapon skill you get a perfect hit an arm pops off the enemy either flees or becomes more enraged. The outcome is death either way bleed over time. It would be odd to have a bunch of one armed bandits around in game. Losing legs dont seem practical unless they fall to the ground at your mercy. A decapitation could be perfect sword skill and still sort of rare. Heavy armor could counter this. Anyhow its worth looking at the fallout 3 segmented bodys and possibly working off that, that general idea.