While it may not be the Superman movie some people wanted or were expecting, there is no doubt Man of Steel is proving insanely popular, breaking box office records in America for June openings. It is already known Wraner Bros. have put a sequel on the fast track, but now we may now how fast that track actually is. According to the Wall Street Journal, citing 'knowledgeable people close to the studio', we may see the sequel as early as 2014 (most likely end of the year), with rumours of the Justice League keeping it's announced release date of 2015.
A quick turn around on movies like this is nothing new, the early Harry Potter movies were given a very short production window, but to me this feels like Warner Bros. are only rushing to compete with Marvel Studios. The problem is Marvel took the time and effort to build the world, characters, and audience anticipation for their cinematic universe. Popularity of Man of Steel aside, Warner Bros. just throwing together their version of this model won't have the same effect. Again, these are only rumours at this stage, but with San Diego Comic-Con, where every major studio will be showing off their slate for the next few years happening in the next few weeks, we might get some official confirmation.