Everything I've heard regarding the production of the "MAN OF STEEL" sequel - both stuff that's widely known and not-easily-confirmed insider gossip - has added up to one conclusion: They don't know what they're doing. Not in an incompetent way, in a "We haven't really settled on what this movie is" way. It's fairly clear that they had a definite plan in place well before "MOS" ever came out, that that plan involved a new Batman showing up, and that they were already working on it to some degree as the first film was rolling out in theaters.
What's equally clear is that Warner Bros. had a Karl Rove on Election Night 2012 reaction - in slow motion - in regards to "MAN OF STEEL's" performance, which they'd forecast as a huge moneymaker and a game-changing fanboy lovefest. Instead? A hit, but not an "AVENGERS" or even an "IRON MAN 3." The audience? Bitterly divided... between "ruined forever!!!" and merely "deeply flawed" - hardly anyone, as far as the pop-culture tea-leaves are concerned, thought it was great.
As a result, whatever the Big Plan was for the sequels and tie-ins has been getting revised on the fly (cameos expanded to supporting characters, plans to split the production in half with the second film being "JUSTICE LEAGUE,") as the studio and filmmakers try to figure out what it is the audience actually wants to see since "More 'Man of Steel" has become clearly not the answer.
Added to all that: The film had been scheduled to hit mid-Summer 2015 - just two month's after "AVENGERS: AGE OF ULTRON" - as part of a cluttered field what was already making that year a blockbuster bloodbath waiting to happen. So it's only a little bit surprising that Warner Bros. has bitten the bullet and moved the film almost a full year ahead to May of 2016. For the kind of money involved, that's a really big deal... but it's probably the best news that could've possibly hit the project. Now they can, potentially, work out a functioning screenplay instead of whatever half-rewritten mess they'd been working from thus far (on the down side: David Goyer is moving with the movie.)
I wonder how much playing release-date tic-tac-toe contributed to this decision. Across town from WB, Disney is still having problems with "STAR WARS: EPISODE VII" (the buzz: nasty power-struggle between J.J. Abrams and LucasFilm boss Kathleen Kennedy for control of the franchise.) They've already moved the film once, from the series' traditional May release date to XMas 2015, and I'd been hearing some say they'd be better going all the way to the following May. The only thing really stopping them was that Big Boss Disney had already staked May 2016 for "Untitled Marvel Project" (presumed to be either "DOCTOR STRANGE" or an unannounced character possibly spinning-off directly from "AGE OF ULTRON") and that they'd promised shareholders they'd meet a 2015 target. Disney would almost certainly have moved the Marvel project to make room for "EPISODE VII," but now they're blocked. This stuff is simply Byzantine, after awhile.
I also wonder if this will lead to any major cast or crew defections. Henry Cavill has really nothing else as major going on (ditto Gal Gadot), but Ben Affleck had another prestige-project movie scheduled to start after he was done shooting this - would he walk and hand back his Batman money to keep that commitment? They've been aggressively pursuing certain actors (The Rock, Jason Momoa, possibly Denzel Washington) and characters (Green Lantern, AquaMan), are any of those commitments solid enough for this to not displace anyone? Goyer's script was already getting a rewrite by Affleck's pal from "ARGO," does he move on? Is this room enough for the Nolan Bros. to wash their hands of the DC movies at last? Hell, does even Snyder maybe depart to make room for someone to helm both movies? There's a lot that can happen here.