5-digiter here and avid reader since nearly the beginning. Few comments since there are far smarter people in the forum than me.
1. Comments are king. We can get the stories anywhere.
2. See #1. More whitespace = less comments we can get to. Kill the overkill on whitespace.
3. See #1. Eye-candy = more noise-to-signal. To paraphrase James Carville, "It's the commentor's info stupid."
4. See# 1. Keep comments rankable, nestable, and filterable by rank. Don't want to see the trash.
5. To paraphrase God and/or Google "Don't be evil." Slashdot's ancestry is right there with the web itself, and the open source and Linux communities. Selling info and linking logins to FB, Twitter, etc. is an abomination.