The only thing I can think of is that they held this film back due to the increasing amount of anti-superhero movies coming out on the back of the Kick-Ass success. Take Defendor for instance with Woody Harrelson, this is exactly the same type of movie as that but with a better script and better executed.
I'd say that if you like Ghost World and Defendor you'll like this movie. I can't think of a time when I would ever rewatch this which makes it sound like I didn't like it, that's not true, it does have a good feel to it and it was quite graphic in parts but it just didn't blow me a away like I thought it was going to. Both Ellen Page and Rainn Wilson were excellent, the Bacon was quite good too but I thought Liv Tyler was a little miscast.
Good but not great, with the cast on show I was expecting a little more.