Some developers who chose one of our competitors ended up switching to JOGL when they learned that the third version of the library you talk about drops AWT support, when they got a lot of troubles with its second version or for another reason. Moreover, I don't think that its website is noticeably better organized than ours because you can easily find the download section on both (2 clicks to download our archive, at least 3 to get its archive), the Java documentation, the forum, the IRC channel and the wiki. Actually, we waste a lot less space as we don't show useless news on the homepage. In my humble opinion, the newbies can make the "wrong" choice at the beginning, it isn't the end of the world. JGO has a lot larger audience than our forum, it won't change any time soon and its moderators are against us. Getting a better forum shouldn't be done to attract more newbies.
I almost always advise StackOverflow users to post rather here so that Sven can give them some good advises too. I have no plan to die yet, I have been in the JOGL boat since 2006 and I am almost sure I'll be there (if alive) in 2026 but I see what you mean. Depending on a very few people is neither healthy nor safe for a project. However, we prevent nobody from contributing.
I still think improving the appearance should be done for better reasons because those newbies who would technically grow could still discover JOGL later. Keep in mind that despite its limitations, WebGL is attracting a lot of developers. Don't expect our community to become a lot larger than now.
I already said that I have nothing against phpBB which is under GPL
We aren't sure that such a migration wouldn't break the permanent links.
As far as I know, phpBB supports the mailing lists.
I don't know, I'm not responsible for that.