
The timing alone would be crazy: - not to mention star Henry Cavill - have literally just finished selling the world on seeing their new Superman vision (and still have some red carpets to walk overseas); the turnaround time from marketing and promoting this first film, filming the sequel, doing months of post-production effects work and then going back out to promote MoS2? Even if it could be done, the quality of that work would be dubious, at best. Snyder himself has recently, and with certain needing to be figured out first, just getting the sequel figured out on paper could take about a year.
A look at Marvel Studios' franchises tells us that the quick turnaround demands of a shared universe can wear down your casts and creative teams. Films like (which is going through due to a rushed production schedule) have fans skeptical about the strategy of altering a working formula for the sake of getting a sequel out quick-fast.
Fearing that the actions of Superman are left unchecked, Batman takes on the Man of Steel, while the world wrestles with what kind of a hero it really needs.
DC/WB may want to get a Superman sequel out soon, yes, but they may want to consider the divisive response to the first film and focus on polishing those wrinkles into a superior sequel. As to the thought of Justice League coming out in 2015: who would direct it? Zack Snyder would be busy with MoS2, and so far his name has been. Henry Cavill would be near dead from exhaustion if he had to knock out another Superman flick and a Justice League flick in the next two years (see again: ) - which is just one more reason why this sounds a little too doubtful to be true.
Man of Steel 2 ( Last Son of Krypton would be my preferred sequel title) in 2015? Justice League 2016 or 2017? That I would be more inclined to believe - that is, if DC/WB is even interested in moving into a team-up that quickly, instead of trying to launch more multi-million-to-billion-dollar solo character franchises featuring Oscar-caliber talent and proven creative teams (Nolan, Goyer, Snyder).