I don't know the status of filler vs. canon material on the anime, but the last canon episode discussion I saw had 40 posts, so regardless of what is being discussed, it's quite apparent that there's still interest in discussing the anime. We're just in the middle of fillers, and as always people don't care to discuss them. When does the canon material return?
As for the manga, well, the latest chapter has 16 replies... in this small forum, I don't see many anime/manga doing the same amount of posts in a single episode/chapter.
Anyways, isn't this series ending sometime soon? I don't think we need any drastic measures at that moment.
When the time comes, and the series ends I'll wait a month or so and just merge the Anime Threads and then merge the Manga Threads, and place them in General Anime and General Manga respectively, and delete the forums.
But until then, I don't think anything is going to be done regardless of how poor one might think the quality of discussion that is happening in those forums at the moment.
From what I can tell, no one participating in this thread so far cares for the Bleach anime/manga discussion, so I don't know how much weight I should put into your considerations.
If the people who are actually discussing them and/or have an interest in discussing them could share their opinion on this matter, then I think I would really consider these "drastic" measures sooner rather than later.
If anything, I'd say wait until the filler arc ends.
Just recently, Naruto was in filler mode and it barely got any discussion. Filler ended, and discussion returned. So I don't think that much consideration needs to be given to low content discussions during this period.