GENIUS SOLUTIONS to the leaver problem.
Now obviously people can win a 4v5 due to skill but most of the time it's not the case as it is too late if the teammate rage quits at like 15-25 minutes into the game after feeding.
If a player INTENTIONALLY presses "Quit" then the team that has to deal with a 4v5 should be given a permanent buff to equal out a loss of a player.
Furthermore so people don't ABUSE this system the player who leaves intentionally should not be allowed to join back into the game and lose normal LP amount they would lose if they stayed. This is so people won't leave on purpose so their team can win 4v5 for them and they still get LP for the win.
Intentional leavers lose LP, team that has to 4v5 has a chance to win.