I must congratulate you on reading this entire series in the first place. I read the first five I believe, but could go no further. The first book I will gladly concede was very nearly fantastic. It was fun, exciting and heroic in all the right ways. I honestly loved it, and could easily see why it was such a phenomenon. The second was also very good, though not quite as brilliant as the first which I suppose is unavoidable in such a case. The third was fine, but nothing more really. A pattern was emerging, but I was hoping that the downturn was a typical lull in a long story arc as things were being developed for future revelation. However, hope can carry you on for only so long, and after the next two I could go no further.
As the books got longer, and more dreary, they seemed to lose any interest in the characters themselves. By the fourth and fifth I found that I hated Harry. He became a snide, nasty, sniveling little egomaniac and I could really find no difference between his character and the villains. That may be fine in some settings, but in a series of books touted as heroic good vs. evil fantasy it just doesn’t work. You simply have to like the hero, and as the series wound on it was clear that there was no hero at all, but merely an incidental protagonist who happened to be a jerk. I simply couldn’t think of reading yet another massive tome about an illtempered primadonna like Potter, and so gave up on them. The rewards of reading the books had disappeared and the costs were hefty. Boring, boring, boring...
So, again, congratulations on the effort. I really don’t know how you did it.