Tilt-avoiding meassures
How about this: After 3 consecutive losses in a row, where 3/3 games were with a bad grade/kda or something that indicates that the player is doing bad, to have a question pop up when you click the play button that says this "Are you sure you want to play another match?" that would dissappear after 10 seconds on its own and you cant dismiss the button in any way.
On the 4th defeat in a row, you'd get a queue ban of 10 minutes, so that it gives you some time to calm down and to like take a break from the cancer inducing behaviour that players have in-game.
On the 5th defeat in a row, you'd get a queue ban of 1 hour for the same reasons,
On the 6th defeat in a row, you'll get a warning that says "for the next 3 hours you'll be losing x2 lp and mmr and you will be getting x1/2 the lp and mmr" so that it discourages people from playing league when they are tilted.
All of the above, reset when you log out of the client for at least 3 hours, or every 24 hours from the last defeat.