I can see why some people would want an Anime sub-forum and I can certainly see some benefits, but I personally think that it would ultimately create far more problems than it solves, and I think it's a really bad idea. If it happened I wouldn't be upset, but disappointed maybe. I wouldn't use such a sub-forum on principle.
Anime is off-topic in the sense that it's off the topic of gaming, and The Escapist is all about gaming as its focus. Anime should be treated just like politics, music, stories, personal stuff etc. Anime is as removed from gaming as any of those other things, so I don't see why all these things can't just live together under "off-topic discussion" as they do currently.