Please consider purging account that are not played, like 90 days or 6 months even.
My rank over the past 2-3 weeks.
- I hit Expert rank (about 4000 Rank)
- Lost several games, and moved to Beginner (about 160,000 rank)
- Lost even more, had a bad streak and moved to Novice (ended up around 1.6 million ranked)
- Won a couple games, moved back to around 160,000 rank
- Won 1-2 more, and back down to around 92,000 rank.
My guess is their are 500,000 players with the same rank, so as you lose/win you move huge amounts on the leader boards.