The low number of reviews is always a problem.
People's time is normally limited, so most people won't play every game. You will also get people who submit, but then don't play or review the games.
Ratings are also never evenly distributed across the submissions, which is why, I think, itch runs a normalisation calculation on the eventual results.
So far I have reviewed 30 games, and only received 10 ratings, but when you consider the most rated game only has 15 ratings as of a few hours ago, 10 ratings sounds pretty good.
Also, just because a game has a lot of ratings, does not necessarily mean it is the favourite, just the most rated.
With so few entries in this jam, it would be nice if everyone was able to try to play everyone else's games, but the reality is that the ratings distribution will never be equal.
One of the things that has always eluded me is how a game is rated as popular on the submissions page, because it never seems to reflect how the games are played by members of the jam, but if you sort by popularity to choose which games to rate in the jam, "popular" games seem to do better than "unpopular" ones, likely because people think popular equals good.