On prior forums I have been on, attempts to split into a only some posters and all posters forums have ended badly.
When there are enouph high class posters, everything goes into the high class forum and the open forum collapses leaving no worthwhile βinβ for new users. When there are too few high class users, everyone double posts to both forums in order to get discussion and you wind up with a functional 1 forum system except with lots of links and more burden and top level menus.
I have not seen an open /β closed forum system with exactly the goldilocks number of high class users to maintain stable equilibria in both forums.
On prior forums I have been on, attempts to split into a only some posters and all posters forums have ended badly.
When there are enouph high class posters, everything goes into the high class forum and the open forum collapses leaving no worthwhile βinβ for new users. When there are too few high class users, everyone double posts to both forums in order to get discussion and you wind up with a functional 1 forum system except with lots of links and more burden and top level menus.
I have not seen an open /β closed forum system with exactly the goldilocks number of high class users to maintain stable equilibria in both forums.