I spend a lot of time on reddit as of late, but putting aside the idiocy that can be present, there's one thing that I really like. When I see a story - especially a science/tech story - I can click onto the comments and immediately see the top-rated ones. What I like about that is that well-informed opinions have opportunities to rise to the top. I know the slider switch is a way of handling that, but I really wish there was a way that I could click on a story and see the highest comments sorted as such.
The one thing that has kept me coming back to /. after all these years is that the people are great and can have a lot of knowledge to share. I wish we had a way to highlight that in a better way.
One thing I do love about Slashdot - if I saw a cool story yesterday, I can actually find it. I like the timeline aspect of that.