I guess I don't understand what you mean by "link directly," but NSFW links appear on the Reddit homepage often, and touching them will open the link in the app's browser. Also, (at least in Alien Blue) I can subscribe to any subreddits I want, including NSFW ones.
By "link directly" we mean that a subreddit devoted solely to NSFW content appears as a default in a list of ones to browse from the moment the app is launched.
You've always been free to add specific NSFW subreddits that you know about after the fact. And NSFW links appearing on the frontpage is an occupational hazard, that quite possibly never happened during the App Store review process.
