The main criticism I had of the second season was that it got a bit too lurid for my taste and it sort of came off as being thrown in there just because the show was on Starz, as if that was a requirement.
But the acting and most of the stories I thought remained pretty strong. I don't think it ended on an anti-climatic note (even though I wish there had been a bit more resolution between Kane and his wife) because they were writing it with the expectation that they were getting a third season. So it was the cliff hanger aspect that left a lot of stuff dangling.
Though at least one story arc seemed to get resolved satisfactorily: Sanaa Lathan's.