I've been reading slashdot for a long time. I have to say that I am impressed. It has evolved into a pretty nice system. I still lament the problem of late posting*, but the moderation system seems to work fairly well. I keep my filter at 4 or above (except when moderating) and rarely see dumb comments. So, bravo to the designers.
I also like this new friend and foe system, despite the fact that it is sort of divisive. For me it will serve as a reminder system as to when someone has written something particularly dumb a number of times, and I want the system to remind me to suspect their writing.
In some ways, I'd like to see the system to be more specific to that. I'd like to see a rating system, so that I can see a list of the people I find consistantly funny, insightful, informative, trollish, offtopic, etc.
In other words, I'd like to be able to moderate every post I decide to read, even if it doesn't affect the actual posting karma.
In fact, I wouldn't even suggest offering to filter on such things, because I think it's important to not filter too much, lest I miss new authors with special insight, or even foes who make a good point, against all odds.
Maybe I should mention this to someone...
*The problem of late posting: Someone who takes a few hours to think about and write a detailed, reasoned response to an article might never get moderated high enough for me to see, because their post is buried in the slushpile of all other posts.