Not that I've ever submitted anything before, but based on experiences at other sites, getting throttled sucks. Having to sit and wait for the clock to reset for each subsequent submission is a pain and extremely unfriendly if the content isn't actually spam.

What if instead of rate-limiting the submissions, HN accepted all the submissions, but then controlled the rate at which they're released into the mix. That way, the user's experience is unencumbered, but there's also not a sudden flood of posts from a single user all at once?