Imagine for a moment that the Airbenders that didn't join the Temples to become Air Nomads (I'll refer to them as "Air Folk"); and they started their own City. What do you think they'd be like? What aspect of these "Air Folk" would you be interested in to see?
They wouldn't be wearing robes and would most likely wear Republic City style clothes but with an Air Nation theme. I figure longer hair might become popular as it is more lively (for a lack of a better term) in the wind. I imagine they'd be more materialistic than the Air Nomads. I don't think there be any (or at least many) Sky Bison or Flying Lemurs around. Most likely variations of Birds/Bird Hybrids. I think they'd invent their own Sport (not sure what'd be but it wouldn't be as carefree as "Air Ball"). Most wouldn't (likely) be Vegetarians.
They'd have Police, Firefighters, Doctors, Merchants, Military, etc. I'd imagine they'd be fairly technological. They'd have Air Ships, Hummingbirds, Planes, Mechs, etc. I think they'd be less technological than Republic City however.
I personally would just like to see this concept as a whole be canonically/officially introduced. I guess I'd be most excited to just see Airbenders that don't live as Monks/Nuns. I want more variety.
What about you?