I would add that while i don't use the official Nintendo thread, i do approve of it, because it does work to bring in smaller posts that likely otherwise wouldn't be thread-worthy, and anything thread-worthy can be spun off into its own discussion at the discretion of anyone who cares to try. Like that Metroid x StarFox rumor (though that originally surfaced in the official Wii U thread) we had quite a few pages of discussion on that rumor in that thread, so it could have been spun off into its own discussion if it didn't quickly become clear that the rumor was fake.
I am in the camp that believes the problems here are structural and cyclical. Structural in part because of too much website subdivision and the removal of sales tools, and cyclical because yes, it is the end of the generation. And the reason that impacts our site more severely than other gaming sites is because we are sales oriented, so once patterns have set in, people are going to care less about a site that specializes in sales. Spam threads have always been an issue, just that there used to be much more "legitimate" activity to counterbalance it.