By now, almost everyone knows who the villains are in Legend of Korra. I think I know what they are. I think they are a cult based around a spirit posing as a false God, who is trying to take over the human world, maybe it's Koh, maybe it's some new, unseen spirit. I think it's one of the only ways to go because, come on, a non bender wont stand a chance against the Avatar State when Korra inevitably faces the leader of the Anti-Benders. This False God in my theory could be much stronger than Korra and make it a much fairer fight than Ozai and Aang, making the final battle more epic and long lasting.
I forgot to add how it requited people. It's possible that it played on nonbenders with bending envy. It's also possible that it used The War as an example as how benders cause trouble, and must not be allowed to be in any powerful positions, or do not even deserve to exist at all.
PS. Go to 1st Avatar's blog and comment.