Story length / votes
In the faq you mention that the shorter the story, the more votes it gets, and "the higher the likelihood of scoring a winning goal for your team". That is why you advise participants to limit the length of their stories.
This is only quantity. You did not say whether short stories got overall higher votes than long stories. Since I take it that the votes are averaged, it should not make a difference how many votes there are for the final result. Only difference: the more people vote, the less weight a vote has.
When looking at the number of comments, stories over 20.000 words (about 40k) score well, stories less than 5000 words attracted generally less comments.
Maybe I'm weird, but I like long stories. I spend the last two weeks reading all the contributions of last year, and was amazed at the high quality of the fics. I'm looking forward to this year's cup, and I hope that there will be a few authors that couldn't stop at 20k ;)