Can users propose a full tree of rankings?

Yeah... As a melomaniac I am scared to see too many genres of music being misused as rankings, like speed metal, black metal, death metal, etc.. I am not against adding these rankings, but I am afraid to see people, who don't quite know what they are talking about, messing around with them. Plus, some rankings, and not just in the music category, can be up to interpretation. I believe you will need a lot of moderators who can form "councils" and vote for the existence of certain types of rankings, or simply create "meta-opiwiki defining polls" where every single user is allowed to vote for or against stuff like that.