Just thinking out loud here, but why not have the table captain poll the judges after each category has been judged then summarize on a comment card? We might get a more even picture of how our entry was judged.
I started out giving cards for 6's but now only 5's or less (why give a card because your product is average).
The argument for requiring a card for a certain score is the same half assed people that won't go the extra inch will just not give that score, thus further inflating the norm.
Ed