I'm going to go with a soft no. This had been brought up before and I think the consensus is
A) no one wants to be One Leg Jimmy begging for coin outside the tavern. Well I won't say no one, but the only ones that would are probably getting their leg cut off on purpose to fulfill the role. The majority of players would see this as a possible halt to everything they want to do. Pretty tough to farm the land with one leg
B) decapitation and limb loss would most likely bump the ESRB to "M" rating and I'm going to assume SbS wants to keep it at "T" in order to expand the potential customer base
Personally, I like the idea. Cutting the head off of a dead NPC or permadead player (especially a Noble) and spiking it at the entrance of the town your bandit party just raided would add a lot of flavour, and I wouldn't mind a town Jimmy to brighten my day, but alas it wouldn't be good for the sake of the game. Think of how easy it would be to grief someone. You find an Explorer, you best him in battle and cut off both if his legs. This may as well be permadeath for this type of playstyle, and could happen within the first hour of entering the world