Derank protection at rank borders is dumb. Why should losses at Platinum 3 count against you, but losses at Platinum 4 are ignored?

Streak bonus is dumb. Why should 3 losses followed by 3 wins be a net gain, but win-loss-win-loss-win-loss goes even? Why should consecutive wins net you bonuses, but consecutive losses do nothing?

Right now, the system's extreme upward tendencies make it substantially less accurate. A loose correlation between winrate and rank means more frustrating matchmaking; if the game can't accurately assemble even teams, one side will stomp, one side will get rolled over, and 10 people are forced to sit through a largely uninteresting game.

Treat every game the same, and let consistent winrate over time determine whether people rise or fall—not how long you're willing to grind until a streak shoves you over a rank border.