I think the problem is that people are too familiar with one aspect of Superman. This film explored other aspects of the character, like his kryptonian heritage, in great depth. Obviously looking at Superman from the angle the film did it seems as if this isn't the character some fans are accustomed to. However I feel that even though this Superman did things we didn't expect him to do (destroy Metropolis during the fight between him and Zod) he is still a very accurate interpretation of the character. If an individual like this existed in real life I think most of what happened in the film would've happened in real life. People need to remember that despite being godlike Superman is no god; he has extraordinary abilities and can do super things but he is also flawed. He is SUPERman not PERFECTman.
A World's Finest film would be amazing. If they're going for a MOS2 next year they need to follow up with a Flash or World's Finest film pronto. After that Wonder Woman and if we're lucky Aquaman (which would be too awesome for words). There is no need to get Justice League out there so quickly.