On the basis of what? Did that trailer intonate bad things to you?
I really don't know. Well, actually I do. The whole thing about Superman is that he's alone. There's no Krypton, very few other Kryptonians. Now, it looks like there's a whole damn army of them fighting it out on Earth. How is this different from a thousand other 'invading-alien-army-overwhelms-earth-except-for-the-one-reason-to-hope' movies? All they've done is shoehorn Superman in it and called it Man Of Steel.
I hope I am wrong. I want to be wrong. But I have been burned by too many sub-par superhero movies to get my hopes up. I should know better than to judge by the efforts of the MCU.