And to suggest that the falling buildings and epic destruction were only there for "entertainment value" just seems silly. It was clearly meant to demonstrate just how scary and powerful and dangerous Zod and his men were, and to give Superman an overwhelming threat to overcome-- because Snyder and Goyer clearly felt that Superman required a much bigger threat than we typically see in a superhero movie.
It's nice that you were entertained by the falling buildings. But the simple fact is that there were enough people who were bored
by them, their minds wandered, and wondered about the human casualties. The movie was a success but there were enough people who felt this that it would really be silly to attribute the criticism to motiveless malice.
As far as so many of the falling buildings being there? It's not because it was trying to make Zod et al. seem scarier and more dangerous and more powerful against Superman. Two or three Kryptonians attacking him at once would have been. One chocking him might have been. One kicking him in the nuts even. But no amount of falling buildings were going to be scary or dangerous or powerful for Superman. They were like people crashing through cardboard.
Scarier and more dangerous and more powerful against the humans? Showing the casualties from one falling building, even in the Smallville sequence would have done that much more effectively. I daresay that actually trying to imagine a global depiction of the World Engine at work could have been much more effective. A supposed world threat limited to some empty ocean and a single city? Well, yes, the script told us. But Snyder and Goyer didn't show us.