You really don't know this, it is just speculation. For me was simple, went as a fair ruler and sided with witches. On my other playthrough went as a strong ruler and sided with demons. So far the only real difference is that on realm 3 you get a real difficult choice if you side with demons (Make a half measure or be a "butcher" that give you even more strong ruler points), while if you side with the witches the problem almost solves by itself (savior).
So from the realm 3 point of view the "right" choice seems to be siding with witches and the "bad" one seems to be siding with demons.
Whatever will happen on the next realms is still to be seen and probably things balance out. But saying siding with demons is the right choice and witches the bad one is a real stretch right now. It is just slightly different content so far, on the outcome of the Elven realm illness and the LI's/side girls of course, Kagome content on 1 side and Seraphina on the other. All other variations from other variables are much less important or impactful... so far of course.