To be fair though, it does have to do with the amount of active users on the forums and the level of users a bit too. You have some (very active) users with a very high level of Japanese over on the WK forums as well as a way bigger user base (For example, I get a notification for every new post made on ALL threads here in the forums, because the activity is relatively low, if I were to do that on the WK forums I would be pinged many times a minute at certain hours of the day).
I would love to contribute to the grammar point discussion and the like, but due to the low activity there I could make a mistake, not be corrected on it for months at a time and in the mean time cause either confusion or straight up mistakes in many other readers, so I stay out of it (as might others), which means lower activity, less chances for corrections… A vicious circle.
The only solution I see is to just ask questions on any thread where you get a problem, with some luck it will draw in more engagement to the threads, cause other users to browse / pay attention to it more and in a while we might see it flourish like the WK discussions.