The black stars are a hard to distinguish from the hollow ones for me, see upper part of the attached image. Maybe color the hollow ones differently in addition?
Done, hollow stars are now gray. Those are some sad-looking stars you've got there though -- no anti-aliasing.
Maybe use a different symbol other than stars for either the fun or the difficulty?
I like stars pretty well, but if there is a really good replacement suggestion, I'll consider it.
Maybe don't display the symbols when a pack has zero votes?
The only way to get zero stars is to have zero votes, but I suppose having zero stars is somewhat misleading. I don't want to leave the cell in the table blank though, so I'll probably leave it for now.