Feeder skill. Pking was one of many consumers in the game (and still is to a lesser extent: Bounty Hunter) while the 3 skills you mentioned are feeder skills into the game; they drive a large part of the game. Problems: Take out those skills, and you'll make several refinement skills (like smithing, cooking, fletching) obsolete... OR ...you'll have to turn what's left, combat, into a feeder skill just like in MapleStory. Somehow I don't see that working in Runescape with its limited geographic size and limited spawns. I don't see too much room to put a ton of monsters that drop raw materials. Even if you made fewer monsters drop more material, you would find that everybody would compete to kill the monsters, causing problems.