To pile on the reasons why beta sucks:
1) The images are almost entirely, but not completely unrelated to the story. It's like someone has access to photostock and scripted an automatic photofinder that adds the first result from the query containing all the tags.
2) The discussions are automatically expanded, which wastes a lot of space. No, I don't want to see only "interesting", or only "intelligent". All that the ratings basically are is "I agree" or "I disagree", with a few lone exceptions for obvious trolling material. Give me the highlights, and let me easily expand and collapse threads. You know, like it does right now.
I have a strong feeling that a lot of the design was cribbed from Ars Technica, but you missed pretty much everything what makes their design work:
1) They have actual editors, including photo editors. That means that the images are frequently awesome creations that add commentary to the headline, and headlines and summaries are actually useful. At Slashdot, the summaries are frequently nothing more than the first paragraph of the article.
2) It's easy to quote people, directly link to comments, and be notified of and find new comments. Beta does neither.
So, for the TLDR crowd (yes, that means you, managers and executives):
No one cares about the front page of Slashdot, because editors have on average sucked since the beginning.
The only thing people care about is the article and the discussion. Make either hard to get to or hard to use, and everyone will leave. I'm sure you noticed that your SlashBI stuff is failing pretty miserably. The same thing will happen to Slashdot if you don't fix the useful information issue of beta.