The reporting system isn't sufficient for every kind of Toxic
There is a small but virulent percentage of the games population that can not be dealt with through the normal system. Players who smurf/throw or whatever to get into lower ranks and then intentionally throw games. My recent experience was a mid lane zed who clearly didn't belong and got a huge lead. he started a flame war with our jungler and spent 30 minutes of the game taking jungle camps and creeps from him, refusing to fight and only interacting with the enemy team when they found him or if they had already fought us and won 5v3. never pushed, never defended, never helped and actively denied our jungler creeps and camps all game not to mention the all chatting the enemy team. The reporting system has an option for griefing but this is so much more, such a level of toxic that a report, even by all his teammates isn't going to have the effect.
I know these people are a small percentage of the players, i've had a handful of these experiences over the 6 seasons of playing so Im not advocating anything drastic but there needs to be a link, an email, a support person, something where these few examples of super toxic people can be sent to for review. Id link the replay but I think that violates the name and shame policy. but if anyone at Riot wants to Ill give them all the info. This guy is the most disgusting of trolls.