2. World-Building Over Character-Building
Despite the epic scale of Man of Steel, there were a lot of areas where the movie felt underdeveloped. Although Zack Snyder did a fantastic job in establishing the Kryptonian side of this new cinematic universe, it felt as if the earthbound side of things were left a little lacking. And with Batman in the picture now, it seems as though the cosmic aspects will be dropped from the story.
One of the most important parts of any onscreen iteration of Superman is the city of Metropolis itself which ironically, is as important to the character as Gotham City is to Batman. However, Metropolis was hardly explored in
Man of Steel unless you count the fact that it was almost annihilated in the third act. The Daily Planet was only there for a handful of exposition scenes, and if Perry White wasn't even in the movie I doubt many people would have noticed. The relationship between Clark Kent and Lois Lane, which is vital to grounding the character of Superman, was barely developed in
Man of Steel. Seeing as it was an origin story/reboot/whatever, it seemed as though they were saving it for the sequel. Despite the best efforts of Amy Adams, Lois Lane amounted to little more than 'damsel in distress'. The problem with introducing Batman to the franchise is that it involves a whole new set of world-building. When you have Batman, you need all the archetypes that come with the character; the Bruce Wayne persona, Alfred, Commissioner Gordon, the Batmobile, and of course Gotham. This is going to require an awful lot of screentime to establish and despite Snyder's undoubted talents as a visual director, there is a chance the all-important human element of the story will be neglected. When the director admits his favorite word is 'awesome', don't expect well-developed characters. Expect explosions.