I agree with many in the main exit thread: Forums aren't dinosaurs OR dying in the niches they occupy. If anything, they're growing. No other social media design captures near-time conversation, topic organization, search-ability, anonymity, and global 'one stop shop' for everything that forum is about. Every other option mentioned (Facebook, G+, Reddit, Discord, etc.) fails one or more of those major features.
Getting rid of the official forum concept is a big mistake, and will almost certainly spawn another forum(s) that are 'unofficial' for fans to get those community features. Iago may be done with the forums, but he's likely to find out after they're changed to read-only that the fan base isn't done with the Forum concept. It'll fracture for a while into all these other SM spaces, then imperfectly coalesce back onto another BBS style forum somewhere else. After Iago breaks the tablets, and the JBO fanbase spends a few months wandering in the FaceBook, Reddit (lol), and G+ desert, perhaps the 17th Shard will take them in. They certainly don't seem to be 'dying'.