I suppose it comes down to what you think this place should be.

A lot of stories receive comments like, "This isn't news" which would suggest some users want this to be a news site. Post types like Show and Site Design as well as the rise of things like AMAs make this more of a community for others. I've also started to notice more posts from non-designers looking for advice or info, so there's that. You mention invite-only creating the community of 'like-minded' designers, but that starts to be a problem when you consider the lengths we ought to be going to as an industry to foster diversity. Maybe there could be stricter rules around posting and moderation, but that amounts to mods deciding what DN should be, likely cutting out sections of the user base.

In short: who knows man? But trying to fight spam by closing the doors feels like cutting off your nose to spite your face.