That said, I haven't read past book one. I would rather read books for adults.
You took the words right out of my mouth, there.
In the run-up to the release of The Deathly Hallows (today, as it happens!) I tried to get back into the series. Four years ago I read all the way up to about half way through Goblet of Fire. I wasn't bored, but I found myself getting distracted by other things. Chiefly, exams. I didn't pick it back up again.
Reading The Philosopher's ("Sorcerer" in the States) Stone is proving quite a challenge for me at 20. Not because its concepts are too deep and its prose is too flowery, but because it's exactly the opposite.
Personally, I HATE flowery prose. For me, an author should tell me where I am, who is there, and what is going on right off the bat. Not necessarily in the first sentence or even paragraph, but I need to be grounded firmly in the book's universe. Rowling wastes no time and gets right to the point. No problem there. Her writing is both articulate and light at the same time. For me, it works. No qualms with the writing at all.
The concepts, whilst derived from a number of sources, are drawn together in an original and interesting way. As someone stated earlier in the thread, she tells the same story as always, but presents it in a way that is wholly fresh and unique to her universe. Each book begins by placing its key players in a difficult situation (someone is trying to steal what lies under the guarded trapdoor, a creature is prowling the school's corridors and petrifying the students, or a high security Prisoner is on the run and he's hunting Harry down); this situation is then explored during the mid-section of the book, and is always resolved by its conclusion. Beginning, Middle, and End. The classic structure. It allows each book to stand on its own two feet, but in the context of a greater continuity (a structure of seven individual parts). Her structuring is fantastic, and any loose ends she leaves at the end of each book are fairly minor on the list of concerns as the reader's primary focus has been the individual story arc of that specific installment.
However, the first two books were written primarily for children. They read like they were written for children. Rowling skips over a number of things that she could have explored in greater detail. Not necessarily by stringing together a number of circumlocutions ripped straight out of the theasaurus. Just little indications of how certain things affect certain characters. Hermione talking to herself in the toilet before the troll attacks would have been welcome, but its absence doesn't hinder the story. I don't blame Rowling at all, as she sticks with the central story and very rarely deviates from it. It remains focused, and manages to keep on the rails. But, as a matter of personal taste (and possibly testament to my maturity as a reader) I prefer a little more depth to add that extra dimension and perspective.
I saw Order of The Phoenix a week ago, and it has inspired me to plough through the early books just so I can get to the nitty gritty. What really appealed to me with the film was the focus on the politics of the Wizard World, and how key figures are always trying to upstage one another in the pursuit of greater authority. But, as is the case in our own reality, they each have their own methods of achieving their goals.
I apologise for ranting on a bit there. When I get the ball rolling I really can't help myself.