The integrity thing sounds complicated. It's better if it's very simple.
There's a lot of cool things that can be done with dismemberment, but I probably won't touch it for a while. The current system is not all it could be but strikes a pretty good balance between novel behavior from losing limbs and a high likelihood that a strike that lands will kill you.
I think a problem with being able to fight without a sword is that you might be good enough at the game to dodge enemy attacks, but not good enough to kill them with your less effective unarmed attacks. You can already see this happening when you lose a leg. The loss of mobility is usually lethal, but skilled players can use their good sense of timing to survive pretty well.