* They went closed-source.
* They removed the cloudsearch syntax from the search API. That may not seem very signifficant since very few people used it for their day to day redditing. But this was the only way of acquiring submissions older than the most recent 1000 for any given subreddit. Now there is no way to obtain old data, short of searching for random keywords and checking the date. I guess they don't want you to benefit from the aggregated data.
* They abandoned iterative development to do a redesign-by-giant-committee. They are just pushing hostile shit and adjust if the complaints get too loud. That's a clear warning sign of things to come.
* They rolled out the redesign on wide scale while it was not even close to alpha state. Half of the endpoints just straight up didn't work, and the remaining half was broken, like flairs, rules, css, and basically everything else.
* The new system refuses to serve hosted image content to non-trackable clients (ie, you need img.png?sid=valid_sid to get image data). It also includes some rather hostile tracking technology, I forget the details but it was described in /r/privacy somewhere.
At this point, it seems like the best thing to do is to set my subreddits to private so at least I am not contributing to their $100M revenue... but yeah, unfortunately it sucks for the community (and possibly other mods interested to keep the place running), hard decision to pull the trigger :/