The funny thing is, I had been pushing for more
categories, including perhaps some catch-all for movies & TV (showbiz if you will), which at times entirely takes over the General category.
From my experience at a smaller forum that uses this type forum software, I'm not sure if "Child" sub-forums work much. People tend to forget they're there at all, and so little or no activity takes place in the child-boards.
It's hard to judge discussion activity cause if there aren't a lot of titles launching, or a lot of buzz building up to a mega-release (ala SWTOR), then you just won't see much discussion going on. And a lot of discussion tends to gradually fade off once a game has been out for a while.
I do know from my own experience running little forums on specific games (from my good old days running little fan sites for Darkstone, Incubation and others), that the more categories you have, the harder it gets to moderate and keep an eye on everything. I perceive that as a benefit of category consolidation. However, I don't really see consolidating as a magical way to increase forum traffic or to make people think the forums are busier than they actually are.
My main consolidation fear is it turns the first page into a mess (see Quarter to Three's "games" forum for example). Of course we can do Searches but those don't find everything, and as a non-console gamer I don't particularly want to wade through a bunch of stuff that's irrelevant to me to find something I'm interested in.
But hey, it's a forum I don't run, not a democracy. So they can do as they will, and I'll attempt to keep posting on what interests me until they kick me out.