I think the problem was caused by less player playing champion league.. so collective climbing slowed down. Yeah a solution would be adding players (also bots is ok to me) but It's not so fast. We are "losing" 30+ chests for season.. Is not much, but well it is appening since few months so it starts to be annoying. The most annoying thing is to be forced to compete for top 50 and champion I at the same time. Not funny at all. To me it would be better reaching champion I few days before the end, then focus on top 50 battling.
I don't have solutions about rework of the rating system, and I also think there are other priorities out there (land!)