I know people keep saying Raven, and it's not like I don't want her in the game, but I think this is a small case of seeing what you want to see.
I mean yeah, she's been know to be a villain on extremely rare occasions, usually demonic takeover stuff etc. but I don't think they would list her with the villains. I know, "the game is in a different universe not the comics, shut up etc." but I don't think it's her in this picture. She could still be in the game, or DLC, or whatever.
I just think it's someone else. Also I'm curious about the Killer Frost theories, was she hinted at at all or is this another we want her in the game sort of thing? Again, not saying she isn't going to be in, just wondering about the basis for it all.