Commentarama Films offers some possible reasons
for why some comic book movies have been thudding recently. One of these is that:
Hollywood is trying to appeal both to fanboys and the public at large while also setting up the franchise for future films. This is an impossible task as these three things call for mutually exclusive requirements. The fanboys want more depth than the comic books. The public doesn't want a learning curve. And nobody wants to feel like they're watching two hours of "this will pay off 2-3 films down the line."
We could even add ruthless greed of the top brass to make money at all costs as another reason. In a time when box office receipts are declining, they're clearly so desperate, they're even willing to risk a wretched screenplay under the assumption that everybody will flock to their production regardless of quality, based on the name value alone. But that does not a long-term strategy make.