I'd be devastated if more boards were closed, as in real life devastated, as in hatemail and spamming porn on the bug reports forum via a dummy account over a proxy server devastated. Same goes for being banned. This is not because I'm a spitefully person, it's because this forum for psychodynamic and personal reasons mean very, very much to me, far more than it's healthy for a internet forum to mean to someone.
Closing boards wont work, because the people that post bad things will just move to the other boards. Banning wont work, because there ill always be new people, or ban dodging. Moderators don't work, because toady dosn't want them and they'd be either to strict or eventually corrupted.
I don't think you can be rid of it, unless you turn the forums into a police state, it's the law if the internet than any community large enough will become a pool of depravity unless ruled whit an iron fist.
Personally, my suggestion is to simply discourage it the same ways that is done now, and hope for the best, I also think that if there was an official link by toady somewhere 90% could be shunted of to
the new VN, which would also allow the main forums for be a little stricter ruled without it becoming unbearable.
I'd say simply MOVE any inappropriate threads to new VN, leaving one of those topic-stumps whit a stern warning and a link to the corresponding NVN topic.