I guess it comes down to two things, really. Flaws with the film, and flaws with the critics. I feel like is people are taken in by the emotion and spectacle, they won't pay as much attention to the overall storytelling. However, it's obvious that many critics want a colorful and optimistic storyline..some even desiring camp. The most critic-pleasing Superman movie would be one that is bright, old-fashioned, and emphasizes the relationships between Clark and Lois.
That being said, I want a slow-paced story that builds into a satisfying finish. I probably won't get what I want, but I'll accept the movie if it means a good sequel will get made.
Also, I've seen some criticisms that have encouraged me. People complaining that Cavill lacks energy seem like they wouldn't accept the more contemplative nature of the character from the comics.
I want the emotional moments to really work, and not be plot-devices.
I don't expect a movie as deep as BB now, but I do expect an intense and psychological thrill-ride.