This is not the CGI action-fest you've been led to expect. That doesn't mean it doesn't have CGI or action (it's got both in spades), but the action pieces - while extremely well choreographed and absolutely necessary to the plot - aren't the heart of this film.
Let me also go out on a limb and throw out another absurd idea: this isn't a zombie movie. Okay, okay, they are referred to as zombies more than a handful of times in the movie, and the film does has a zee (zed?) in the title, so I think I'm on my own there. But it struck me how different the approach to zombies was in this film to the point that it feels more like an action-adventure than pigeon-holed genre fare. There's an absence of gore for gore's sake (a zombie-film favourite), and shock-jump moments are used sparingly to make them all the more impactful. If we're trying to stick a genre label on this film, it struck me more as a race-against-time outbreak film than anything resembling a zombie flick. But part of that has to do with the global scale.
In almost every case I can call into memory, a zombie film is centered around the idea of isolation and containment - a premise that the "survivors" are alone in their struggles, and tough they may come across other survivors, there's little understanding of what's actually happening on a large scale - how other regions, countries and continents are handling the epidemic. Sometimes there's an off-hand reference or TV info-drop describing the global situation, but World War Z gives us a wonderful picture of this epidemic spreading worldwide because we actually get to see it with our own eyes. We are introduced to the ways different cultures and countries have attempted to deal with the problem they are all facing simultaneously, and we are along for the ride as we see how that works out for them. And that's a cool new idea.
Pitt's Gerry is a refreshingly balanced protagonist. He's not an action hero in the physical sense, and the film doesn't seem to need to flex much muscle there. But he's sharp as a tack and very quick-thinking throughout the film, and that's what keeps him (and countless others) alive. There are a few moments garnering disbelief that won't need to be spoiled to be obvious, but otherwise his character is quite compelling and it's clear what his motivations are throughout.
I also quite enjoyed the way the script weaves in and out various other characters throughout Gerry's journey to discover the truth, balancing their expendability with their own determination and resolve to survive. Most compelling for me are the relationship Gerry develops with the stoic Mossad agent Segen and assumed ward Tomas. And although there is a heartfelt believability demonstrated in Gerry's relationship with his own family, it's in his exchanges and earnestness with his non-kin that demonstrate the real heart of his character.
Although I'm on the fence about Forster as a director (one of his films, Stranger than Fiction is high on my list), he does a masterful job with World War Z, balancing epic set pieces, maintaining engagement and sense of place through complex action sequences and delivering compelling relationships. I'm also impressed with the restraint shown in the script itself; I'm aware of multiple rewrites and am familiar with the source material, but just like my hesitancy to extol Forster as a director, I know how hit-and-miss Goddard/Lindelof team-ups can be and was thrilled to see a much more well-rounded script on display here.
Overall, it's a refreshing new grand-scale addition to the zombie genre. If you want to call it that.