Rather start with my personal mental map of "gaming" I thought it might be useful to look out at what RPG communities people joined in Google+, both because I think the self sorting gives interesting insights, and because G+ has been very important to the RPG space., and it is going away, leaving a gap. Here's a list of most of the communities over an arbitrary 2000 count. (I stopped bothering for the last maybe a dozen D&D groups I encountered)
G+ Tabletop Roleplaying Games 28688
Roleplaying Games 17040
Dungeons and Dragons 15458
Dungeon World Tavern 11262
Fate Core 11207
Game Master Tip 8730
Pathfinder RPG 8378
Dungeons and Dragons 5th Edition 7435
D&D 5th edition 6614
Dungeons and Dragons -DND Fans 6399
Powered by the Apocalypse 4848
Pen and Paper RPG Bloggers 4577
Gaming on the Cheap 4577
Chaosium Inc 4123
Library of Gaming Maps 4044
RGP Session Prep 3971
Numernera Fans 3363
Call of Cthulu RPG 3122
Tabletop Podcasts 3100
Star Wars D6 Roleplaying Game 3100
Fate Accelerated 2906
Shadow of the Demon Lord 2761
13th Age 2592
Sine Nomine RPGs 2560
Monster of the Week Roadhouse 2216
The Black Hack 2092
Lamentations of the Flame Princess 2086
Pelgrane Press RPGs 2080
The Gauntlet 2058
Lone Wolf Roleplaying 2012
My read on this is that people rally around games systems and publishers, but that there are probably a few topics that could be a productive seeds for "system neutral" discussions like "Game Master/Tips and Prep" or Tabletop Podcasts and Actual Plays.
It seems clear that we need spaces for a Fate, Power by the Apocalypse, and OSR both based on the popularity of their G+ communities, and because lots of indie creators build these game around these three categories. For example, I have a Fate based game here, and importantly, Evil Hat, the creators of Fate, are selling their games here. Have any other major indie publishers done that?
It might be useful to have a D&D forum, even if Wizards nevers sells here, so that the 80% market share gorilla plays nicely by itself, and doesn't accidently stifle other conversations accidently.
It probably worth considering what the big three "generic RPG" communities had as categories. At the the very least, that way of breaking things up didn't harm there success.
If someone had expertise on the LARP or boardgame side, it might be nice to undertake a similar stab at the data from those communities.
Not data driven, but conjectural based uniques nature of itch, it probably makes sense to have
- an RPG Kickstarter category, so those people can find that content, and so it doesn't spread everywhere. (Being in other, relevant places is fine, to I'd want to read about a new Powered by the Apocalypse game in a place with people hung out talking about PbtA)
- I'd personally value a space to highlight and talk about games by/about people not traditionally centered in tabletop RPGs (probably relevant to board games and LARPs too) This would be discussion in addition all the other relevant spaces.
- dedicated new release sections for tabletop RPG, Board Games, and LARPs.
I'd be willing to help out with moderation, if you need more people to pitch in. I professionally managed a 2000 member forum as part of my job responsibilities for 5 years. (Of course, the community consisted of mostly middle aged women who lead small community based healthcare programs, who were fierce and focused, but in a different way than many gamers, so I'm sure there would be plenty of things to learn by doing,) Beyond playing and designing and discussing) TT RPGs, I play a fair bit of boards games (but don't hand out on board game online spaces and have play some LARPs, even they are a huge hobby focus.