Bronze shouldn't exist.
All it does: Other players get a quantifiable way to tell you're bad at the game, you get no reward because the rank itself is a participation trophy for losers, and you get to feel bad about yourself over a game.
What I propose is a longer placement period (20 games), and a pass/no pass system. If you don't prove within those games that you're at least at the Silver level, you don't get a rank and you get a week to look up guides and/or practice in norms before you can try again. This way, players have to prove they're actually ready for a serious game mode instead of just being stuck down in a completely worthless league.
This would benefit a large number of players, keeping them from a mode they're not actually ready for so they can learn that just reaching level 30 doesn't prepare you to be an asset to a team.