It seems like the evil Superman theory is pretty much debunked. I could envision a scene like in JL War where Superman is in Darksied's custody.
I'm more hyped for this movie than I have been for pretty much any other post-Nolan superhero movie.
I hope we don't get an evil Superman. As a huge Superman fan I'd hate to see that. As been mentioned, we haven't seen a mature and well loved Superman yet so it is way too early to turn him evil even if it just briefly! We just started seeing people starting to trust him by the end of Batman v Superman.