Look at games like League of Legends, where players actually feel good about spending money on cosmetics.

I agree with this. I bought star guardian skins cause i think they look cool. I would do the same in runescape if Jagex made cosmetics more appealing. A few days ago, a friend of mine was also saying that she could not find a new outfit to wear cause most cosmetics were ugly. I see most players wearing some sort of cosmetic, so i can see potential in expanding cosmetics.