Nothing inherently bad with being edgy. There is also nothing inherently good about it.it is a buzzword rendered meaningless by overuse, one of many buzzwords that studios keep trying to substitute for good. I don't care if you are the edgiest, most hardcore movie or the sweetest most playful one, as long as its a good movie.
I also don't find Man of Steel to be particularly edgy. That's not a criticism of the movie, but when they keep talking about it as if it is, it rings false and not sure what it means for what they consider edgy moving forward.