Re: bbPress as standalone project (as fork)
bbPress _must_ not become a WordPress plugin. First of all because a BBS isn’t always associated with a blog and in my case this never happens. bbPress gain the attentions of a lot of people tired of bloatware engine like phpBB or slow engine like vBullettin. I switched to bbPress on all my sites for these reason.
Seconded a lot of people (as far as I know) chose bbPress because they can access to a WordPress style plugin system. If you have ever written a plugin for WordPress you can edit a bbPress one easily in order to accommodate your needs. But if bbPress will be a plugin of WordPress you will download a plugin… of a plugin? This is kind of confusing IMHO. Obviously I’m not talking about PHP programmers or in general skilled people but of regular users.
Third I think that the bbPress project deserve its own space. It is a too well done piece of code and for being a mere WordPress plugin.