I'm not sure about this idea... In my mind, Japanese Entertainment is separate enough to be it's own category. Threads about anime & magna don't really seem like they belong in the General Entertainment section, especially on a forum like this where a large percentage of the community does watch anime/read manga. I understand the premise that it is the Japanese version of Culture & Media, and that does seem reasonable to warrant a merge, but the thing is that anime and manga etc are such prominent areas of discussion that in my mind they should have their own section. Perhaps like Scarf said, it could be better to change Japanese Entertainment to Anime & Manga (or similar) and clear up the loose ends in between for the rest of Japanese entertainment by putting them in with General Entertainment? Or possibly even just make Japanese Entertainment a sub-forum of General Entertainment if something has to move? It just seems unfitting to have anime/manga discussions taking up General Entertainment to me. And I don't think the acitivty of the sections should matter too much if it means the topics stay in the correct places; we have much less active sections that are standing alone.
I don't often post in either section though so I may be wrong here and I apologise for making any unfair assumptions. :p