I was thinking maybe something like:

1) Number of votes made and average rating of each file.
2) How many votes of 5, 4, 3, etc there have been.
3) Only 1 vote per file. Currently you can keep voting for the same file as long as you clear your cache.
4) List of registered users who have rated the file and list of votes cast in user profile.

That is all I can think of right now but I think these will improve the rating element of files.