I think it was slightly more than that. First off it was a Hollywood movie with no clear good guys and bad guys - you didn't want the humans to win, but you didn't want the mutants to win either really. And that's something when blockbusters usually spoon-feed you exactly what to think. Not only that, I though it had some depth as well - at least, it made me think about the ethics of the issues involved, and had a lot to say about alienation. Plus there were some very cool action sequences
Having just seen it though, I pretty much agree with you otherwise. It was ok, enjoyable, but nothing amazing. probably one of the better blockbusters this year.