Even a ahand or feet is way too much. Just imagine how wide an arrow tip is. Arrows do not (usually) shatter on impact, thy thrust and thrusting is not too good for cutting things off. The only think I can imgine being cut off by an arrow is a finger or ear. Skill should not have much to do with this. With blades for instance, the better you are the LESS messy you can be, not the other way round. And cutting off heads should be very, and I mean VERY, rare. It sounds nice and easy, but there are many things in your throat that make decapitation quite difficult. Cutting pleople literally in half should be feat only possible for non-human creaturs, like the Gatekeeper in SI of similar. Probably rarely for a minotaur, but nothing human-sized should be able to do this and definitely not a human being, no metter how strong or skilled.
Besides, a game doesn't HAVE to be rated M to be a good game.
They do not have to be "M" rated to be good, but they have to be at least "M" to be realistic. The real world is AO and worse if you ask me. Sorry for your parents.