Putting aside all other issues with CC, the ranking system itself does not hold a candle to the Feast ranking system. The current system is a weird two part system roiled into one with no promos and thin lines between promoting and demoting tiers.
If crystal rank is kept, we would have to modify it a bit for how many points a person would lose on average per tier. In Feast it was -5 on bronze loss, -10 on silver loss, -15 on gold loss, -20 on plat loss, and finally -25 on diamond loss. It could simply be shifted, so bronze loses no points and every other tier loses 5 points less. Crystal promos would start at 2500.
Note for those that did not play Feast:
We used to earn on average 25 points per win. When you hit certain thresholds, you entered promos. If you won 3 of the next 5 games, you were promoted to the next tier with your points still going up and down throughout the process. To demote, you would have to fall 100 points below that promotional threshold. For example Gold promos were at 1000 points. If a player achieved gold but fell below 900 at a later time, they would demote. In addition, no player could go above 100 points of a threshold point without successfully completing promos.