I think it has merit, Alex. The key to it being successful would be to set some guidelines for the sort of info to post, and to keep chatter in the thread to a minimum - fine to provide additional info or opinions on a site, but if its OT then don't post.
My suggestions would be:
Title: State, Region, Nearest Town, Name of Site
e.g. NSW, Sydney Metro, Kirrawee, Alice's Place
e.g. NSW, Central West, Burraga, Burraga Dam
e.g. NSW, Central Coast, Central Mangrove, Pony Club
Body:
Public or private
Description of site and facilities
Restrictions (e.g. no dogs, separate parking, subject to flooding, etc)
Camping or no camping
If public - directions to get there, GPS coords, etc
If private - best way to contact the owner (think about this people - do you really want your phone number published on a public forum? I'd suggest a PM to the relevant member of IIS).
Just my suggestions as food for thought.
BTW there is a lot of good information on campsites in both the WikiCamps App, and the Camps7 Book. Not all camp sites are good for astronomy, but quite a lot are, and its especially important if you want to camp at the dark sky site.
Al.