FWIW I worked on this japanese grammar site which breaks down the grammar much more atomically: http://jgram.org/
But I'm not sure how to categorize in an organized way all these individual grammar points like these LV2 items:
these are more like sentence patterns. very useful, but hard to group. maybe a lot of these are modals or connections, eg "based on / because of / despite / the more you A the more B " ... but i'd like some type of ontology to organize things at a higher level.