Many people, myself included, would love for Christian Bale's Batman to be in the untitled 'Man Of Steel' Sequel. Yet, Nolan's world contains no Super Powers? So how could this go about working knowing what has already been established in both franchises?
Let's be honest, Man Of Steel was not as big a game changer as 'The Dark Knight Trilogy' was, but it effectively did its job. Introducing Superman to the modern world. and while the SDCC announcement about the sequel was surprising, many fans' hearts sank when Christian Bale said he has hung up his cape and cowl. So, unless they surprise the world by announcing Bale's involvement, this is strictly hypothetical.
Knowing what has been established in The Dark Knight Trilogy, Super Powered-Beings do NOT exist, we can understand why people automatically threw that possibility out the window. But, given that MoS is a first contact kind of movie, with aliens and stuff, wouldn't merging the 'Nolanverse' With MoS be the best way to go about it. If the whole world, in MoS, was surprised to find out about alien life then would the already established Bruce Wayne (Bale) be just as shocked, and try to make contact with Superman? To me this seems like the only way they could go about introducing Batman into 'Man Of Steel 2."