My opinion in a nutshell.
I would have to agree with Dutch Baka for several reasons.
1. If the Administration can find the time to start a NEW FORUM for China, they should be able to have the time to do this for J-pop.
2. I have blocked the J-pop category partly for the reasons given in the OP. If there was a separate category for just regular popular Japanese music, a la Dreams Come True, Spitz, Puffy, etc., I would not block that unless it turned into the same condition as J-rock is now. Somehow I doubt that would happen any time soon.
3. I have posted in the current J-pop section on a few occasions. Therefore it is true that I for one do have interest in J-pop, but the current torrent of J-rock posts acts as a deterrent to my reading/posting of said threads.
4. It is a high traffic area, so it seems to me to deserve some special attention and categorization to foster its health. I think DB's suggestion is a good start.
That's all for now. I have to get to bed soon!