Fall of Brad Pitt

I'm one of the big fans of Brad pit but by watching "World War Z" which was released recently i've changed my mind. . As if he play an amateur movie.

Is that real Brad Pitt who played in "The Assassination of Jesse James by the Coward Robert Ford" with his unique and  distinguished style  ??
is he still able to act like Detective David in Seven ??
Today i decided to watch world war z because Brad Pitt was on it. the movie was about virus which was spread among people around the world and make them zombie.
The movie was totally bullshit and it's highly recommended if you wanna waste your time .
Hope to see Brad Pitt acts like before. He shouldn't see acting as a business like Nicholas Cage who acts for money .