I agree with a lot of the criticism so far, especially the pacing and the character connections and their back stories.
From episode 2 to 4, Ray and Antigone's investigation is essentially where it should have been the day after episode 1, when Casper was discovered. It strikes me that the focus of this season isn't so much the actual murder (indeed, it seems like the resolution will be rather pedestrian), as it is the interconnectedness of all the players involved. It seems that the main concern here, and one could call it the main character, is the city of Vinci itself and all of the corruption that comes with it (so much screen time is devoted to that grotesque brown haze). And I can be fine with that...I only wonder if we will get a hashed-out resolution only at the very end as piles of strange coincidences fall onto each other in a series of revelations that would have been realized within a week of the investigation. I really don't care that the investigation is more or less ancillary to the corruption plot or the characters, but I feel that we are just being strong along for no reason, and dumped too deep in the middle of all of these back stories that have no hope of full discovery.
One thing I disagree with, though: the dialogue. I love all of it. I'm a whore for Don Delillo and this type of writing--where every character essentially has the same voice and serve as vehicles for the author to spit out profound monologues. It's really the only reason I watched the first season and it's what keeps me watching this one. That being said, Vaughn can't deliver those scenes properly. He's fine when he's bashing faces and while I think his lines are superb, he just don't have that capacity to make these lines as terrifying and innocent as they command. I know this never would have happened, but someone like DiCaprio would have been perfect in this role.
I'm hoping that, like The Wire, this 2nd season is the black sheep season of the series.