Wouldn't be easier to have 2 global pool about this?
My idea is to put 2 option into the launcher to vote. One is chosing a champion to buff, and another for a champion to nerf. It wouldn't force anything just give a statistic on what players would like to see somewhere on the boards.
I know popular champions would get tons of buff vote. Well that's why the nerf vote is there. If a champion is popular and strong, then even more player for ask for it's nerf.