The big issue for me isn't violence qua violence (haven't seen the "qua" construction for awhile, now, eh?)...rather, it's the drawn-out nature of these movies. This one clocks in at 2:35. The common description between the reviews (and there are others that do the same...) is describing/complaining about "endless" conversations between Matt Dillon and Bruno Ganz.
That could still be good, if the material (and the actor) was really up to snuff. You really need someone who can pull off the dialogue, though, and Matt Dillon has always been more of a shambling, suburban-NYC Brandoesque mumbler...
If you're going to go incomprehensible, then follow the lead of Lynne Ramsay with YOU WERE NEVER REALLY THERE, and make thing 90 minutes long. (Of course, now that I say that, she probably will come out with a 3-hour director's cut in a few years...)