Actually, the underrepresented continent is easily Asia. We have: a token Chinese leader, a token Indian leader, a token Japanese leader, a token Persian leader and a token SEA leader. That's about as close to a bare minimum as it gets. We still don't have anyone representing Central Asia, the Turks or Mesopotamia. I hope the last unrevealed leader is someone that does.
America is also looking bleak with it's 4.5 leaders, 2.5 of which are America-adjacent, but the choices there are generally more inspired and interesting.