I want this to be good but the timing does not seem great. Green Lantern at best underperformed (some would say flopped). Superman is being revived and while Man of Steel looks good so far, no-one knows how it will perform. A poor or lukewarm reception, coming after Superman Returns, will make it very difficult to relaunch Mr Kent as a cinematic hero, be it in a solo or ensemble movie. And Wonder Woman remains in developmental limbo.
About the only things that make sense re the timing (in my opinion) are, firstly, the success of The Avengers. And enough has been said about the way Marvel led up to it with the solo outings, as opposed to this (apparently) standalone movie that I don't need to rehearse it again.
The second thing is that Chris Nolan's Batman saga is now coming to an end and doubtless WB will look to revive/ reboot/ relaunch Mr Dark Knight ASAP. It may be that a more fantastical Batman, who pals around with the super-powered and battles enemies from outer space, is just the way to go, in order to distinguish the new take on the Caped Crusader from the most recent one. And this would save them from going down the Amazing Spider-man route, and re-telling his origins again.
But even that is open to dispute; audiences who flocked to Noloan's dark, reality-based take on Bats may be (Bat-shark) repelled by a more fantastic take on the material.
Count me in the reserve judgement camp.