Change to Leaderboards and how they work:
New board: Most Reviews. Ranked by total reviews completed, with accuracy breaking ties. No minimum to appear — it's now the first tab you land on.
Total Accuracy now actually ranks by accuracy. It was sorting by level first and only using accuracy as a tiebreak, so someone on 55% could outrank someone on 95%. Fixed. It now needs 500+ lifetime reviews to place, so the top isn't decided by someone who answered three questions correctly.
Most Painful Kanji is retired. It ranked characters rather than people, so nobody could place on it.