1. lack of search 2. "expired links" when clicking on "more", without any description of what is going on 3. "expired links" when you are commenting and take much time to submit your comment 4. no hints during comment reply saying whether there are any formatting rules/conventions which can be used (like quoting, lists etc) 5. no possibility to do comment preview
I agree that at least for some of these there is some rationale behind, but still it's far from being "simple because perfect".
In other words, do you think a free service that was created recently and isn't especially pretty can be successful, but if the site is generating revenue from those users the design becomes problematic?
(btw I think ebay is the only truly ugly site in that article, and I think hn looks just fine).
How are you able to assess the ROI, when even YC takes a 5-10-year look at their portfolio, and a 100-year look at language design?