I think introducing random items when skilling will make the game less repetitive in a way, such as when fishing for sharks for example you know you will be banking 28 raw sharks over and over again, however if you introduced say caskets at a 0.5%? droprate it wouldn't be as repetitive as it's not guaranteed you will be banking 28 sharks all the time, same with woodcutting maybe a 0.5% droprate of nests with random items inside, as mining has the gems so I guess it's only fair really.