* They're launching new user profiles that center around the user; see the Washington post's Reddit account
* Reddit's model of communities is fundamentally broken. Each sub, unless STRONGLY curated like AskHistorians, develops its own hivemind. Post against the grain and receive downvotes, then take the downvote train as people LOVE to pile on downvotes.
* Reddit's upvote / downvote system is fundamentally broken. Easy to parse, light content or quips / jokes get hundreds of upvotes while actual, informational but boring responses get buried way below.
* Reddit has BLATANT advertising masquerading as user posts to big subs like Pics or MildyInteresting, or TodayILearned. Perfect usage of brand names, convenient brand symbol or product positioned perfectly, etc. And somehow posts that are straight up advertising get thousands of upvotes quickly.
* Reddit has done nothing about certain subreddits automatically banning people who post in X Y Z other subreddits, regardless of the content of their response.
* Their CEO, Spez, shadow edited people's comments in the_donald without telling anyone. Ellen Pao even commented on this and nothing fucking happened.
Etc. there are plus sides to reddit, but very few subs worth commenting in unless you have the popular opinion.