Fascinating set of proposals, thanks for posting them here. They seem to fall under the general category of 'automatic gain control': http://en.wikipedia.org/wiki/Automatic_gain_control

As the 'noise' of submissions goes up, a system that automatically adapts to the amount of activity in order to determine constitutes the 'signal' will probably help HN readers cope.

I think OP's problem stems mostly from the format in which (s)he reads HN. Checking the frontpage two or three times a day doesn't lead to the same kind of overload as the RSS might. Whereas when checking the frontpage you'll see a mostly stable set of articles (with most of the churn down at the bottom few), on the RSS feed you'll see every single article that hit the frontpage regardless of how short of period of time it spent there.

Perhaps, a quick fix for HN readers coming here from RSS feeds might simply be to not send every story out via RSS, but say, only those stories that stayed on the frontpage for >1 hour.

I really liked your option to hide already already viewed stories, although I would want to explicitly hide them, because there are interesting posts that I want to come back to.

With a hide button I could go down the page and quickly hide all the "social" stories about get a date, pick a grad school, the latest twitter app, Arrington bashing, and go straight to the good stuff like Erlang. ;-)