Bitcointalk really just has one purpose now and theymos has one job, and that is to make sure satoshi's posts remain accessible and in tact.
You don't need a working forum for that, just archiving would be enough.
The source is always better than the archive. Even in Bitcointalk's case where the forum migrated from bitcoin.org.
I don't know a single forum that offers the same level of freedom of speech as Bitcointalk.
I do, but they are all notorious havens for the worst trolls society has to offer. Bitcointalk is unique b/c of the paid signature aspect. It increases activity at the expense of degrading quality of discussion.