Just a quick write up because I am bored on the topic of game bans and chat bans. I myself haven't ever been banned (I think?) so I'm not saying this as some way to justify myself in any way.
I have a friend I play with who has been permanently banned about 30 times by his count. He is extremely verbally toxic but for the most part always tries to win the game and doesn't intentionally feed or anything. This is my issue with the system at the basic level, the level where bans are split into the two categories of chat bans and game bans.
My friend and others like him can simply play and go off verbally all game, every game. And very quickly get banned. Him and many others who have been in this situation then just move on to making a fresh account to keep playing. The cycle repeats. In my opinion before a game ban a player should have to go through multiple chat restrictions assuming he isn't behaving badly in non-verbal ways. This would keep them unable to chew people out but still let them play the game. A few things have happened recently to make this a good avenue of punishment imo.
1) The ping system is now vastly improved so communication can be done entirely with pings.
2) The emote system allows players to let their team know they made a good play etc without the person talking in chat. Also as far as I know it'd be impossible to be toxic with emotes. Sure they can spam the unhappy poppy but that's vastly different to verbal abuse.
3) The new account levelling system keeps players attached to an account more than the previous system. A lot of these players who are verbally abusive will perhaps rethink their chat usage given the time of longer chat bans as a result of not wanting to lose their account.
4) Same as above now that honour is tied to rewards I feel this could be utilised to curb verbally abusive people. Say if someone got chat banned and had honour set to 0 for the duration of the ban. They would regret not having any rewards in the form of chests/honor capsules etc. Have it so their honour resets to the baseline honour level (unless they were already 0) after chat ban is up. They can then get some rewards but not many. They are more likely to be motivated to move up in honour and learn to not be verbally abusive.
I could name a few more points but they are mostly small. My overall point is that by just game banning verbally abusive people it doesn't really do much for toxicity when making a new account is free and easy. A lot of these types of players even just buy accounts due to their ban speed not allowing them to hit higher levels quickly or get many champs etc. So in a way banning people so quickly for chat behaviour enables account botters and sellers.
Game restrictions should be more frequently dished out for actual in game behaviours like griefing, trolling or leaving games. Of course Riot would need to improve the ingame behaviour detection (but that's another thread). Chat restrictions should be for behaviour in the chat. Of course if someone goes through many chat bans and doesn't improve then start game bans but I feel like people who reach that point are likely invested enough in the game and their behaviour to just make another account.
I personally think the reason Riot hasn't overhauled the ban/punishment system is because they like toxic people making new accounts and spending money on rp for boosts, champions and skins. The friend I've spoke of has spent thousands possibly on his many accounts even though he knows they get banned.