Two more remarks.
1. The ELO calculation after a game includes a winning chance for each player. That uses the difference in the regular ELO formula. For the ELO formula modified due to the consecutive wins penalty, the displayed winning chance value is no longer valid; you have been displaying false information for the players for several months now.
2. The top players in Arena and top players on all-time leaderboard begin to overlap less and less; I witness this in Century: Spice Road, but I expect similar changes for other games. The reason is that players who play more often (this includes players at the top of the Arena rankings) are hit harder by the win streak penalty, and thus fall behind on the all-time rankings. (Of course, the overlap was never close to 100%, but the effect is still noticable.)
I encourage you to actually go and check the all-time rankings in Century: Spice Road; most of the top all-time players play at a very low rate, some of them barely enough to show up on the rankings.
Historically, I have a 93% win rate, and I used to spend a good portion of the time at 900+ rating, occasionally even reaching 1000. My win rate is 96% for the last thousand or so games (since the ELO update), yet I cannot go beyond 900, even struggling to maintain 850. How is this modified ELO a good measure of skill, when it is lower, even though I play better? Meanwhile, players who play e.g. 1 game per week are not affected by the win streak penalty, and maintain their old rating.