Now that I've had a chance to watch the trailer in quiet (mostly because the sound seemed really deep to me), I was able come to a conclusion. I figure at this point it may have already been suggested and rolled about some, but to me the reason for the "dark" Superman may be because DC will be presenting the Justice Lords timeline in this movie as the means to introduce the Justice League. I made this correlation mostly on the idea where it is the one timeline where the Justice League is acting outside of their known characteristics and it seems very convenient to be able to transition out of the first Superman movie to a lighter roll for the Superman character. In any case, my favorite screenshots are below with the 'False God' screenshot being the deciding shot for why I think we'll be getting an alternate reality movie.
|The alternate reality where the Justice Lords rule|
|"Normal" reality Superman concerned at the alternate reality or about to dispense justice in the alternate reality|
|Justice Lord Superman|
|Alternate reality Metropolis|
|Alternate reality Batman, possibly in Wayne Manor?|
|Batsuit designed to fight Justice Lord version of Superman?|