The fact that my sh*tty little game is ranked higher than some of the MUCH nicer and better looking/playing/feeling games I saw in the jam makes me not super confident in the ranking system. I think a simpler voting system would be better (maybe just like/dislike, what does 4 stars even mean? What separates 3 stars from 4 stars?)
While not a gamejam, Steam Greenlight had a thing where they just feed you a random queue of games and you could only vote yes or no. I think that for larger jams that's the way to go. With enough rates, it will average out to a usable score.