Well, now that I have seen it, I can understand why people are a tad befuddled by the whole thing. It's not at all what 99% of people are going to expect. It is, as someone else said, primarily an alien invasion story - and a pretty frickin' scary one at that, which was something I wouldn't have anticipated in a million years.
Many of the criticisms are valid and how people react will depend on how much those things bother them. The wanton destruction is completely wanton, and a little disturbing, but the movie makes no bones about going for an operatic scale. Like most Snyder movies, it goes for big, testosterone-y conflict most of the time - but does much better than most of his movies at some subtle, tender moments. For instance, Clark and Lois' love affair is established in two, we-are-here-for-each-other hand squeezes that were quite remarkable.There's a coldness to it that goes beyond its steely palette (I see what you did there, Zack!). Particularly early on the deeply emotional family scenes are too thinly written for their pathos to truly sink in. For instance, I'd have liked to have seen Jonathon's point of view more clearly established as being about his own inability to bear losing his son should the truth about him become known.
That said, it is ballsy, risky, and refreshing for not repeating the now-completely-monotonous beats of a superhero movie. This is not your daddy's Superman. Hell, it's not even my Superman- it is an entirely more grown up animal in both its themes and viciousness. And I think that's what's freaking people out. You just don't expect that out of Superman.
Does that mean something has been lost? Give me a break. There's many different interpretations of Superman on screen, and a zillion more in print. There's room for one of them to be this. It may not please people with a, shall we say, mainstream view of superheroes - but I like it when someone finds a rather unmined vein in these stories. I think it keeps them fresh. As far as I know, no Superman origin story has ever handled his introduction to humanity this way.
There's lots more to say, but right now my conclusion is that it is really interesting as an interpretation of Superman, and an enjoyable, if somewhat exhausting and tense, movie. I feel like I felt at the end of the first time I watched The Terminator.