Keep in mind that the JP playerbase use the forums differently, in comparison to the English playerbase. While you will generally see a larger number of threads popping up on the English forums, the JP players are more likely to consolidate their feedback to much fewer threads (if not limiting it to just one thread).
They're also more inclined to use the Like button to indicate that they agree with someone's post, without having to post that fact in the thread. So a thread might have less pages than a similar one on the English forums, while having more players actually being part of the thread (through the amount of likes).