The key to fixing ranks
You need a lower rank than Bronze. The bottom line is most people get bronze. 50% or more win rate can still get you bronze. But bronze also includes the absolute worst players. 20% win rates can be matched in the same game as you as soon as you place, and the bottom line is these people play so bad they throw. How else do they get 20% win rate.
However if you add a lower division, these people will eventually fall lower than new players, and then not get matched with newer players. This way you wouldn't start off with people throwing in your games after you place.
Having a lower division benefits everyone, because it isn't even good for the 20% win rate players in bronze. They get 20% win rate because they cannot compete with other players. This just means they lose all the time.
Please add a lower division riot.