System that catches toxic players is already implemented. Its active. Its done. There are no people manually checking it, Riot isnt investing anymore resources into it.
Inherently a stupid idea. It doesn't take much to find a completely unjustified autoban post in these forums. People saying "fuck you" or "please report x" about a guy that just dropped a bunch of racial slurrs an or is running down mid and the former gets a 2 week ban because "fuck you" and report requests are considered toxic. Have your ban bot look up the word "context" rito.
Trolls on the other hands cannot be handled automatically. Its hard to catch. Also most "trolls" arent really trolls. They are just considered trolls by weakminded(stupid) people. Like people consider "troll" someone who doesnt gank as jungler. Or someone who picks strange picks on strange roles. Like Jarvan support or Teemo jungle or picking mage like Taliyah bottom lane instead of Marksman(there is no ADC role just BOTTOM). Also they call "troll" players with negative score whom they blame for loss. Also people call "trolls" people who go afk(???) which is very idiotic.
There's a difference between going off meta and having a bad game, and going 0/12/0 and refusing to listen to the team's request for you to build tank items to stop the bleeding. The first is just a bad game and it happens. But there will be obvious play patters (like farming at tower and building certain items) that will make it apparent that the player is at least trying. But when my top lane renekton is 0/5/0 and is still trying to build ravenous hydra as his first item at 20 mins, that's when I lose my shit. This is a team game and your decision affect the entire team. When the team types something in chat, usually (not always, as there are some complete asshats out there) it's in an attempt to give the team a better chance of victory. To blatantly deny that chance at victory by not paying attention to the needs of the team should no go unpunished if the player makes a habit of it. It's downright selfish, and has no place in a game like this. What I'm talking about may not be considered true trolling, but it ruins games in the same way.