Rowling is a good "world builder", and her writing style is very evocative. But her plot logic is paper thin at best, and her sense of character dynamics is utter crap. HBP is the first book where Rowling's pluses no longer total more than her minuses.
In other words you want a story where all the characters make logical choices that are in their own self interest.
In other words, the opposite of real life, a.k.a Star Trek Voyager, a.k.a. dullsville.
No thanks.
for Dumbledore to have essentially been hunting Horcruxes (to have the ring and know about the goblet-locket) before he knew that's what Voldemort had made (also, why does Slughorn feel such guilt for telling Riddle, couldn't he have just come to the details from someone else or from a book)?