This actually is in the game.
It need certain weapon skill at the right part (and a certain amount of damgare) to break a monster part. If it happens, you'll see a part missing.Certain mobs, like great buffalo, only drop certain items in that way
I don't think we'll ever see an entire limb taken off (it's a T game after all), but is a nice mechanism and i really hope they don't rid it.