Honestly, for every tier, there should be a threshold. Starting *** 1 with 2 star, you can start being matched with the upper league because you are close to get there and it's normal that you start playing vs the upper league. But before that, nope. And match with the bottom of the upper league, not the top. Seeing for exemple, a bronze 3 (the worsts players) with a silver 1 is stupid and will be an heavy weight for the person who is about to turn gold. And it's true for any ranking. With the current pool of player, it should be easily doable.