>how about a otaku culture board for discussing otaku culture and other types of otaku stuff

There are already multiple boards for that.

>a NEET/hikikomori board for people who don't work or go to school and stay at home and live with their parents

It's called Personal.

>a Japan general discussion board to discuss Japan and Japanese culture.

You're trolling now, right?
There's no way someone would think a board like this would go well in an anonymous English site.
It's prime flame material.

Also, ''otaku culture'' boards bring out the worst shitposters to sites, and most of those guys aren't really into the specified hobbies, they just want to be as random as possible.