-There should be different kinds of karma, so that you can indicate what behavior you're referring to.
-People with a lot of positive karma should be able to give out more karma to others.
- N00bs should not be able to give karma, until they have some positive karma.
- Posts that accumulate large negative score should be deleted. We don't want to bother reading something the majority of people doesn't like, do we?
- Threads with positive karma should float up and change color, and get some kind of blinking icon.
-People with large negative karma should be automatically tagged with appropriate tags, like "moron", "idiot", "troll", etc.
-People with large amounts of positive karma should be also tagged, like "awesome dude", "community defender", "the guy we all agree with", etc.
- For emergency cases there should be some kind of "shut the fuck up" button, which greatly decreases the karma of the target at the expense of your own.
- Add features that would make the forum similar to RPGs: hit points, skills, classes, etc. Like on forumwarz.
- Restrict the length of posts. I mean, who would want to read through 8 KB of bullshit just to vote someone up or down? That's inefficient.
- All the karma information should be updates in near real-time through AJAX.
- There should be something on this forums that uses Google technology, because Google is awesome.
That's my modest opinion. If you don't like my opinion, it's just your opinion. Remember, having discussions is not that important. The important thing it to be social and promote niceness of the community, and participate, and contribute. Also, if you're against negative karma you support trolls.