Leagues have nothing to do with your rating. They are based on how much you play the game, not how good or accurate your play is. Similar to the way Duolingo works. You’ll move up leagues if you do more lessons than everyone else in your league, not by improving necessarily. So all it means if you get matched against a champion league player is that they are more dedicated to the game than you, not necessarily that they are better.
Plus the fact that once you enter a league you can never go back down, and there's no trophy penalty for losing. This means someone in legend league could be on a losing streak and play a low elo player who's still in bronze
I lost 50 ELO in less than an hour because of your system.