My biggest issue with World War Z was how incredibly tame it felt. There are several responses to the film that mention how even with a PG-13 rating that the film is still incredibly intense and thrilling. I'd have to disagree and I would rather use the word entertaining.
The novel by Max Brooks (son of filmmaker Mel) is subtitled "An Oral History of the Zombie War". The book is a series of individual collections and accounts as a member of the United Nations postwar commission attempts to gather information through oral interviews and other documents. For the purposes of the movie, the plot has been changed to follow a United Nations investigator named Gerry Lane (Brad Pitt) who experiences the zombie breakout firsthand. The scale of this film is impressive and is rarely seen in zombie films which often take place in contained scenarios and here this film moves from the U.S. to South Korea to Jerusalem to the British isles. I do have to compliment the filmmakers' abilities to adapt such challenging material because the movie does capture some of the themes present in the original source novel such as how conflict changes social, religious, political, and environmental landscapes. Brad Pitt is commanding in a very 'typical leading-man in a PG-13 summer action blockbuster movie role' sort of way. He is capable of better performances, but this seems to be just more of a safe role for him and it does speak to how tame the movie is.
Yes it's ultimately a good movie, but it could be more intense. It could be more scary. It tries to be a different type of zombie movie, but it's basically the blockbuster version of 28 Days Later and packs nowhere near as much of an emotional wallop as that movie does. The versatile director Marc Forster (who according to the press had a troubled shoot with this film) does a great job of relating the zombie epidemic to the times we are in with chaos, war, and economic turmoil. Yet, as fun as the movie can be, it certainly needs something more than a metaphor to warrant the praise I feel others have been giving it.