I swear this thread has already been done, anyway, I'll say in here what I said in there.
It makes sense for WB to wait it off, by releasing it in summer you get all the kids who are on summer holidays, where as in November, parents might have spent most of their money on presents already, which makes it a risky time to release.
They're a business, not your mom... They're in it to make money, not to please you, simple as that.
It also allows them to polish the film in terms of CGI and other detailed effects.
I'm guessing by the pretty poor teaser trailer they put out they've atleast completed all filming and the majority of is footage edited up, even if they did stick a pretty piss poor excuse for titling on there... seriously, turquoise water background?? what were they thinking... would've been better just to leave it black...