I have been reading Kuroshitsuji since the summer of 2008, when only a few chapters were translated to English. For about four years now, I have been following the manga. The series has a good premise, is very interesting, and the art is nice and clean. However, now at 14 volumes, I think the manga lacks a distinct and forward main plot. I understand that Ciel works for the Queen while also using Sebastian to discover the true perpetrators of the death of his family, however, I think the series has become slow. I honestly don't know why things are happening now. Ciel just continues to get jobs from the Queen. And that has been going on for 14 volumes now. I am a little disappointed with the introduction of the new arc - the school arc, because I fear the story is just reverting back to the same formula with yet again another order from the Queen. However, I can not be sure yet. I have a feeling that eventually, like all of the arcs, something WILL happen to further the story at least a little bit. Right now, though, the school arc just isn't to my taste.
The good thing is that with the last arc - the ship/zombie story - many character developments and revelations occurred, and I believe the dark undertones fit the manga. I'm glad the shinigami were included again. I hope that their world will be further explored in the manga, because it is intriguing and will open up the manga more, I think.
Overall, in the manga, I do believe some good developments have happened, at least. I'm just concerned that not enough has happened in the 14 volumes released so far. But, I have a feeling the manga will have many more volumes (I HOPE) that will answer questions and develop Ciel and Sebastian. In a way, I hope maybe that Yana Toboso will create a part 2 of the series in which Ciel is older by a few years, that way we can see his maturity. To be honest, I thought Ciel would look at least a little older after all of these volumes, but I guess he looks a bit younger due to Toboso's changing art style or something.
Something else that irks me a little is
the fact that Ciel is so relentless and cruel ( circus arc). I understand that it gives a new dynamic to the series, creating a protagonist that is not completely good, however, bringing in dark scenes ( like Ciel's heartless response to the circus people) completely contrasts with the one chapter fun-time stories that Toboso includes which are usually lighthearted ( like most recently, the Easter chapter). He draws the line between good and evil. He lies, he deceives, and he has no mercy for those he deems not worthy. Because he is a child, his philosophy on human beings seems strange and too insightful, but perhaps it is because of his traumatic past. Maybe Ciel represents the jadedness and corruption of children who are exposed to horrible incidents.
I still read this manga because I do enjoy it and I've invested much in it ( like buying the English volumes ). But, as I've read the story, I've noticed unfortunate drawbacks that I've expressed here. To me, many things can make the story more concise and better. But, I'm sure the author is working on it, gradually, in her own vision. So, I don't mind waiting for now as the story hopefully expands. Kuroshitsuji still has many great elements (Victorian Era, nice mix of the supernatural and the darkness, shinigami, demons, Ciel and Sebastian's contract), but it angers me to see them become overridden with the poor factors in the story.