There are many passages that parasitize reading, and that are unnecessary to the plot, many superfluous descriptions too. The first volumes were shorter, more concentrated, and much more pleasant to read. Here, it seems that the sauce is diluted, the more frame seems much less consistent than in the first volumes. We took classes and the love stories, but the small side police investigation that I loved so much is not as far getaways in Hogwarts corridors and secret passages missing from this volume.
But growing up, Harry also loses humor, I find, to find himself entangled in love stories that, while not unattractive, take too places compared to the little importance they have on the plot.
It still remains very readable, with a removed and precise style.