As Somebody Who's Been Perma'd 8 Times, Here's How To Stop Toxicity
Just give players the option to mute themselves before a game starts, without the option to reverse it after the game starts. We already can mute our entire team, the entire enemy team, or both, whenever we feel like it, don't know why this isn't option.
We have pings for just about everything, and now with League Voice, not to mention Discord and several other voice chat apps, communication would not be an issue.
This isn't just for heavily toxic players, either. Imagine all the times a perfectly fine player got tilted after an incredibly bad game, and ends up losing it the very next game and flames their entire team, and has the Honor Level 5 they worked so hard for dropped all the way to Honor Level 0. I've seen that happen to often.
Over a course of 4 years, and a half, I've been permabanned at least 7 times, 10 at most, and I've lost count in all honesty. All of the bans came purely from flaming my team in chat. I 100% believe that if you just gave players the option to mute thmselves, a surprisingly large portion of toxicity would disappears in just a few weeks.
Chat restrictions are a joke of a punishment, and rarely, if ever, work. Most people who are chat restricted will say so in champ select, once the game starts, or in the end of game lobby, spouting something along the lines of "you guys are lucky I'm chat restricted." At least, this is what I've seen most frequently in other players, myself included. Not only that, but chat restricted players, again myself included, will most times just save their chat for when they really, REALLY want to flame somebody.
Sure, you can argue that this gives a free pass for players who lack self control, but if player is truly aware of just how toxic they can be in chat, and chooses to mute themselves, not just for themselves but for their teammates, they have more than enough self control. Besides, it's not like Riot can go to player to player and give them a whole class on self control.
Edit: Like everybody else that's ever suggested this idea, it's been downvoted. Glad to see people still hate the idea of giving toxic people a chance to not be toxic.