There are some ideas here for getting different content to the front page.
Perhaps someone, after they've made a submission, could "pay to promote" - paying with a lockout of their account for 48 hours, or loss of downvoting, or somesuch, to give their post a smidgen of front page attention.
That means that the people just churning submissions at the rate of 6 a day have to carry on with their scattergun approach, and other people who really think they have an interesting article could give it more attention but with some pain to themselves.
Perhaps someone, after they've made a submission, could "pay to promote" - paying with a lockout of their account for 48 hours, or loss of downvoting, or somesuch, to give their post a smidgen of front page attention.
That means that the people just churning submissions at the rate of 6 a day have to carry on with their scattergun approach, and other people who really think they have an interesting article could give it more attention but with some pain to themselves.