I don't think he's going to be a villain so much as 'a misguided seeker' ala Beyonder.
He's probably trying to figure out what went wrong with his world and is using the DC Universe Earths to find out how to fix it.
And since he was already on the path of losing his humanity, along with human compassion and intimacy, in Watchmen, he's probably reached a point where he's lost sight of understanding human nature. Which is the key component to what he's looking for.
That's my guess anyways.