I really hope they keep Ryuuko as the villain. No more shit about trying to make her a protagonist. Just kill her off and be fucking done with it. Her being a villain would do loads of good for the narrative and make it a lot more interesting than it's been.
And it'd be effective, too. She'd be a very tragic villain. She was the one person who wanted the best for everyone, but she had too many psychological issues -- in the end, she does fail Satsuki's test to see who's strongest --
got corrupted by REVOCS, and eventually died after turning on her best friends.