It's a teaser trailer, and the CGI feels unfinished, which one can expect in a teaser trailer, but it seems they are going the running zombies route. Now, normally I don't mind fast zombies so long as they are done well, but this is World War Z. I mean, zombies being slow is a major part of the plot. What gives?

I'm still looking forward to it. I'm just a bit warier about it now. I still think that Slow Zombies are the "true" zombies, creating an atmosphere that is unique to them, but can still be terrifying. Fast zombies, in my opinion, could easily be replaced by any other monster.

That said, World War Z is about people, not zombies. I guess we'll see.