Ah, I see. Guess it's kind of tricky. I think that the grammar, vocab can go in the writing system portion of Japanese area. With only 77 topics, Japanese writing sub-forum is not getting much love anyway.
The General discussion has sort of taken broad topics. It lists youtube videos, pronunciation, land mass, train rides, etc. on top of language itself.
Maybe it can be:
Main Forum - Japanese
General (society, observations, culture, etc.),
Learning Resources (web-sites, books, locations, etc.),
Language (writing, grammar, vocabulary, etc.),
Assessment and Jobs (JLPT, College, ALT, etc.)
Seeing that Writing System and JLPT has the fewest posts, it's probably better to expand their functions. This can hone the general, but not by much. Learning Resources seems pretty good as is.