The situation IS evolving still, and we will likely see more WHFB style games come and go. Also this covid year has been bad for gaming. Activity in the different subfora might change when people get to meet each other again and play games.
For example
The Ninth Age: despite it having 1K+ threads, T9A discussion has been mainly supported by visitors from T9A forum. It was active five years ago, but seems to have dried up already two years ago, as that gaming community seems to have encapsulated. Does it need an own subforum?
Kings of War: never seems to have been that popular in here, and has seen little discussion over the past year or two. The game is older than T9A, and some of the threads go back almost ten years by now.
9th ed/Warhammer Armies Project: people simply write into the Elector Count's, or mention the game passingly in their B&P plogs. I guess that is warranted since the game is a direct WHFB iteration which takes place in the Warhammer setting. It doesn't even have a name of its own, just 9th ed!
Then we have a big reveal coming, probably this year, as GW plans their return to the Old World. Depending on the approach of that game, it might fit the WHFB line or warrant its own subforum alongside WHFB and AoS. It might sweep the table clean of competitive 'middle-school' type fantasy battles iterations, such as KoW and Oathmark, or it might lead into these games becoming more popular, or even both. Thus, it might be wise to wait and see what kind of a game the W:TOW is before altering the subfora.
I don't mean to speculate. Just warming up the discussion of why we group these games as we do.
-Z