Around the release of the starter kit and the PHB any extended discussion of 5e was banned from the main chat room due to some contentious conversations basically crowding out everything else. In the months since I believe heads have cooled and no one really seems to be having big debates anymore over the system. As such, I think we should be able to allow 5e to be openly talked about in main chat.
I believe it's probably time. Heads have cooled, there are plenty of resources and real games running.
Also things are more awkward and hard to moderate (for mods and users) now that those conversations are partitioned off into another room.
I'd second the move to end the prohibition with a single caveat.
Let's be mindful of those in the main room who have little interest in 5e. Part of the reason it's been beneficial to segment is that 5e can sometimes take over the main room. Let's commit to moving extended conversations on the subject to the 5e room (or another relevant side room), and also to take future contentious arguments elsewhere.
(This is a fundamentally sound strategy for any extended or contentious topic, so I don't see why it would be a problem, but it should probably be made explicit here).