Room for Improvement on Chat Restrictions
Over the course of the last few years, I feel like Riot has made strides in fixing the problems with player behavior in LoL. However, the current state feels very quick to punish in regards to chat restriction, and gives players little to no information about the punishment system. The problem is compounded because the chat restriction also carries with it a negative reinforcement: players are no longer rewarded for their good play with ranked rewards (assuming they restricted at the end of the season) and hextech crafting loot. Even people that have no desire to be toxic/get chat restricted end up getting punished. Everyone has days where they get frustrated with trolls, personal performance, or something else, and losing your hextech rewards and being unable to communicate useful information feels like getting hit while you are down. Personally, it makes me even less cooperative. Then, when your chat restriction is finally up, you are STILL unable to receive hextech loot.
The most outstanding problem that needs attention is the negative reinforcement in the system. By themselves the chat restrictions completely (95%+) fix the problem, but they aren't a punishment. The removal of the hextech loot is the punishment, and it often lasts several times longer than the chat restriction. Unless you only play League to flame people, losing the hextech loot is the only downside to being chat restricted. There's no measure of your progress either, so guess what? I'm eventually going to break and flame that mid lane Teemo, who decides he is going top to feed and you can just deal with it, until the homely scent of pan-fried yordle fills the rift. Worst case scenario, I get chat banned again.
Now that that's out there.... Here's my 2 cents on improving the system.
Limit the hextech restrictions to the same number of games as the chat restriction - I get chat banned, I lose the rewards for X number of games. I get rewarded for serving my time by getting access to the loot again.
Warnings - I pray that one game can't result in a chat restriction (aside from verified racism/homophobic remarks/things of that nature). Everyone has bad games and gets set off every once in a while. If a player is on tilt, the warning will let them know that they are toeing the line, and encourage them to be friendlier in their upcoming games. (Remind them that chat restriction affects hextech loot!) The people that don't care probably deserve a chat restriction, but some people don't realize that their behavior might get themselves banned, and a little warning would probably set them straight.
Positive reinforcement - Rather than focus on punishment, incentivize good behavior. Especially with the hextech crafting system, there are hundreds of little things that could be done to encourage teamwork, good communication, and reward it. Punishing me for negative behavior encourages me to be less negative, but it doesn't provide any incentive for me to be good. If every 5 honors i get earns me an extra key fragment, I would be MUCH more likely to try and earn honors and more likely to use the honor system (which again, goes almost unused now).
Remove penalties/punishment after someone leaves a game - League of Legends is an e-Sport, so act like it. If you have a scheduled baseball game you don't have enough players, you forfeit. Same thing if someone leaves part way through the game. The new /remake feature is a nice step in the right direction. But, I'm in Platinum and I still frequently get AFKs/ragequits in my games and I know its worse in the lower divisions. Once someone leaves, its almost a guaranteed loss and you can bet that everyone else is tilted. Yet you still lose points and can get reported. Right now, if someone quits on my team, I get punished for it, and getting punished for no reason is frustrating. After someone is gone long enough, the game is no longer fair. Sitting in a 4v5 for 20-40 minutes because you cant surrender/your team won't wastes everyone's time, and you cant remove yourself from the event (you can still get banned for being the 2nd AFK) so you will just tilt harder and harder. Not to mention the inevitable "GG ez" from the team with 5 at the end.
Copy DotA if you have to. If you leave games you get low priority queue/banned and you still lose the rating. After X amount of time passes, everyone else can abandon the game and it doesn't count against them. If someone flames a teammate hard enough that they ragequit, I guarantee that they will do it again and eventually get banned. If you don't have a reliable internet connection, don't play ranked. Ranked is a competitive environment.
Integrated Voice Chat - Admittedly this one seems like wishful thinking. The reason text chat becomes so toxic is because it is so impersonal. You ego steps in with voice chat. Nobody wants to be thought as "that twenty year old dude who was throwing a temper tantrum." Think about pathetic you would look at a baseball game yelling out things that you type in League. If someone really annoys you, it would take 1s to mute them. If you also consider how impractical typing is 90% of the time in league, the fact that there is no voice chat is even more ridiculous. It is impossible to effectively relay vital information over text in team fights (by the time you said "Backup for 5s while my CD's come up, then turn" it would be too late, or you would die trying to type it).
/rant