Everyone has dealt with toxic teammates, and they usually rear their ugliest heads in ranked queues. The issue that we have is the fact that the tribunal has proven to be largely ineffective. Jerks haven't gone down in quantity, but rather doubled.
My proposal is to include an in-game, squelch vote system that would put power into the moment in time that it is needed. Trolls and jerks have to be dealt with on the spot, not 1 week later and on a maybe. Also, I realize that you can mute the individual, but it doesn't attack the problem that they need to be shut down immediately.
The idea is a system of unanimous votes that would then silence the player from chat for the rest of the game. It could be reversed at any time, but it also displayed a written message to all in game that they were squelched. This would kind of prove to be an embarrassment for them and could aid in tribunals. Riot could also implement a ban based on amount of times squelched. Where, if you hit 10 you get dropped into lower priority queues (Which are quite cancerous). Hit 20 in a set period, and you get banned for a week.
The most important part however, is it puts power into the communities hand to deal with the problem on the spot, and to actually bring meaning to the vote they had. If players faced a certain ban for telling someone to kill themselves, they will most likely hold their tongues.
Now I am not saying that this is a bullet proof plan, but something has to change. Riot is a company and companies only increase in value if they continue to grow. League has seen a mass exodus due to the fact that the community is more toxic than Chernobyl. Something has to change, and it has to be something that can be implemented on the spot.