Good point about the level-naming: I agree that a "beginner" level shouldn't really be included in the rankings at all, but as you may have guessed I deliberately kept the names the same as Minesweeper, so I blame that!

Notwithstanding the ranking positions, I think there's little doubt that the best Nonogram solvers are the best players on Genius and Expert, but I deliberately wanted to make it so that there are other ways of moving up the rankings, to give more variety in the play. I don't see much point in unweighted rankings, not because they don't show who is the best player (they probably do), but because they will almost always be the same as the expert rankings, so you might as well use those.
(Having thought about this, I can now see your point in wanting averaged level rankings, so I'll look into doing that when I have time.)
Anyway, (as with the Best Times listing where I put newer scores first,) I think it's fair to say that I've probably sacrificed a small bit of accuracy/purity in order to increase the enjoyment/interest levels and keep people coming back to the game.
Oh, the trials of being a game writer...