Win streak bonus is breaking the rating system. Players could still progress, and progression can be made even more entertaining with Multi League implementation, allowing also for better rewarding of good players in lower leagues.
At least 50 000 chests will be farmed by lvl one bots just this season, maybe 100 000 or more, according to my estimations.

P.S. Wouldn't hurt you to give a small upvote for a post based on in-depth research and trying to help with a problem that's been noticed over a year ago and not truly addressed yet.