Just to throw 2 cents in... I think if you create too many subforums early on it could limit community interactions. Think of a dhamma center, they usually have one big hall where lots of different things happen at different times. Each conversation within a forum is like a little circle, a discussion room of its own.
I think a sense of community sometimes gets lost when too many boxes are set up and everything is divided up, compartmentalized. Having broad general forums allows for greater range in a discussion.
Over time a few more forums might be helpful, as you see the need arising from overcrowding or confusion, imo.
Oh, one other suggestion, how about a "General Dharma Talk"
subarea in the General Dhamma section? They have that over at Drolma's site, for General discussion of dharma, not specific to particular traditions.
A topic such as retro started for comparison of Theravada and Zen might
fit better over there then in the Modern Theravada section.
Maybe, maybe not....
end of 2 cents, or was it 3 cents?