RuneScape doesn't have a storyline because it's basically a game where you can escape from your real life in order to try your hand at slaying dragons and casting spells. If there was a storyline, everything about it would change. Since there is none, you can do whatever you feel and not have to go along with anything. I'm sorry that you don't find anything interesting about RuneScape anymore, but adding a storyline simply wouldn't work.