I have an idea for the promotion of this movie. Because Batman is getting more hype than Superman, they just ride that on out and have the first teaser and previews about Batman and his perspective. Maybe the trailer even portrays Superman as possibly being the bad guy.
As the release date gets closer, they release another teaser from Superman's perspective, that shows the other side to the story and fills in some of the questions. The final trailer could show everyone together, and fans start thinking, "oh man, who IS the bad guy in this fight?"
Queue merchandising from all the big vendors with "VS" packaging. Cool Ranch Doritos is Batman, Nacho Cheese is Superman. Bam.