Idea for Increasing Community Cohesion
Taking a leaf out of Uber's book, Riot should explore the possibility of players rating one another after each game. 1 to 5 star rating based on the experience playing the player.
People will be queued with other people of a similar rating as much as possible.
This could encourage players to play with their teammates in mind, listen and cooperate with their team, and be gracious with their opposition.
Those players that Riot continually receive negative feedback about will find themselves playing with other players that also have negative feedback associated with them. They will then have the opportunity to learn what is expected of a LOL player, while those that display the traits of the desired behaviour will have the opportunity to play with similar players.