For me this movie was also a let down after the magnificent Dogville (2004). I didn`t mind it repeating a similar formula, but this time the satire was too flat (von Trier is imho not good at comic timing) and as wpqx pointed out, a lot of the stuff that happened was very predictable. Overall this was a rather preachy effort, where I thought that von Trier should have listened better during history classes. 
A bit like the twin brother of Michael Moore`s Fahrenheit 9/11 (2004) it doesn`t have any revelations to offer, and pretends to be smarter thanit actually is.
Imo, overall a very mediocre and unbalanced effort that leaves much to be desired while at least offering enough food for thought.