AKB48 only got their own subsection after their thread had 60+ pages! TNX girl threads don't even have that much all of their threads combined. The Possible only has 20+ pages cuz every single small newsbit of them used to be posted there, but they aren't anymore. Anyway, the need for such a section just isn't big enough, imo.
Combining Eggs with TNX doesn't really make sense because Eggs are still H!P, TNX are not.
I think keeping TNX with H!P is actually going to give them more attention than if they were separate. It's SO easy to ignore a subsection that doesn't interest you, whereas sometimes people may feel bored and "check out that Possible single thread, whatever that is" when it's mixed with other threads you would check anyway. (I sure know I had no idea about GAM releases because their news were posted in Ayaya forum, which I never read)
Also, about H!P Egg threads - you may start threads for H!P Eggs in the member forum and some of them already have theirs. Nocchi and Kanon come to mind. It's just that the threads are dead, and they wouldn't be any less dead if they were in their own forum section.
You gotta at first prove that there's actual NEED for a subsection and I don't think there is in this case. We've got what, 5 people who care about Eggs/TNX? That's NOT enough for a subsection, and it would only drive away more potential fans who are too lazy to check a separate subforum, but might check a news thread/member thread if it was mixed with H!P.