"... Also submitted four days ago: ...although it gains very few upvotes, and no comments ..."

If this wasn't re-posted I wouldn't be able to read it as I missed the first submission. Maybe a suggestion would be having an additional link of 'resumitted' ie: http://news.ycombinator.com/resub Then you can catchup on interesting articles previously submitted.

As for gaming - submissions has always been flakey. A simple check in the submission code could against previous submissions. Rejecting slight differences in a url.