I thought Harry's newfound Gothiness (though no one actually called it that) was entertaining and somewhat endearing. So age-15.
I am really beginning to love Snape. How could Harry possibly hate Snape the same amount he hated Umbridge? Umbridge was utterly detestable and without any style at all. Snape at least gets mega style points.
Harry's difficult relationship with Cho was hilarious. Some of the dialogue, especially Ron and Hermione quizzing him about his first kiss, had me giggling so much that it was interfering with my reading-aloud abilities.
In general I liked JKR's dialogue. It was the strongest point, and carried the story much more effectively than the narrative did – though she did have an occasional metaphor or observation that made me chuckle.
I thought for sure that after Sirius's death, Harry would end up crying on Cho's shoulder, the way she kept doing to him over Cedric. It would have been nicely symmetrical. But it didn't happen, which kind of disappointed me. Ah, well.
Nitpicky detail: it is mentioned that as winter approaches, the school gets so cold that students are wearing gloves and scarves in the corridors. Um...they can make the ceiling of the Great Hall reflect the weather outside, including an illusion of falling snow; they can Vanish substances, heal broken bones, and seal doors shut with ease; but they haven't figured out a magical way to do central heating yet? Hard to believe. Maybe the cold is supposed to build character or something.
And then there's the wordiness. This will sound mean-spirited, perhaps, but I kept thinking of that line in Wonder Boys while reading OotP: "This kid needs an editor." Of course, JKR has an editor; she probably has several, in fact. So why didn't they cut down the text a little more? Writing is rewriting, they tell us, and my rewriter's eye kept snagging on a word here, a phrase there, which I would have deleted if it had been up to me. I seriously think I could have cut 4,000 words from this book without anyone, even JKR, noticing. Let's take an example passage:
'How am I getting there?' he asked Mrs. Weasley, trying to sound unconcerned.
'Arthur's taking you to work with him,' said Mrs. Weasley gently.
Mr. Weasley smiled encouragingly at Harry across the table. 'You can wait in my office until it's time for the hearing,' he said.
OK, it works, it's not badly written. But it could be shorter. See: a) it doesn't really matter who Harry addresses the question to; it's Mrs. Weasley who answers and that's good enough; b) don't need the "gently"; Mrs. W. is hardly going to be rude to Harry on such an occasion; c) definitely don't need the "encouragingly." Mr. W. is always encouraging. So, with that editing, we now have:
'How am I getting there?' he asked, trying to sound unconcerned.
'Arthur's taking you to work with him,' said Mrs. Weasley.
Mr. Weasley smiled at Harry across the table. 'You can wait in my office until it's time for the hearing,' he said.
Hardly reads any differently, right? And we've taken 47 words down to 43, leaving us with 91.5% of the text.
Look at another example, and notice how every character's line here is marked with an adverb:
'No marks again, then, Potter,' said Snape maliciously, emptying Harry's cauldron with a wave of his wand. 'You will write me an essay on the correct composition of this potion, indicating how and why you went wrong, to be handed in next lesson, do you understand?'
'Yes,' said Harry furiously. Snape had already given them home-work and he had Quidditch practice this evening; this would mean another couple of sleepless nights. It did not seem possible that he had awoken that morning feeling very happy. All he felt now was a fervent desire for this day to end.
'Maybe I'll skive off Divination,' he said glumly, as they stood in the courtyard after lunch, the wind whipping at the hems of robes and brims of hats. 'I'll pretend to be ill and do Snape's essay instead, then I won't have to stay up half the night.'
'You can't skive off Divination,' said Hermione severely.
'Hark who's talking, you walked out of Divination, you hate Trelawney!' said Ron indignantly.
'I don't hate her,' said Hermione loftily.
I would cut the "maliciously" – it's completely self-evident that Snape is being malicious. Could also replace "said Harry furiously" with "snarled Harry." Verbs are stronger than adverbs, and less wordy. I can let "glumly" stand, and maybe even "severely," though that one could be deleted and an exclamation point added to Hermione's line instead. I'd definitely cut "indignantly"; once again it's obvious that Ron is feeling indignant from what he says. "Loftily" – well, it could stay or go, but let's let it stay. So that's 3 words cut, from 175 to 172. We've kept a whole 98.2% of this passage.
Thus, on a rough average, I could edit the book down to 94.8% of its original size. This could reduce 870 pages down to 825. Still a big book, sure, but how many copies were sold again? Five million on the first day, in the U.S. alone? That's 225 million pages that wouldn't have been printed. Think of the trees we'd have saved, all at the expense of a few useless adverbs!
Anyway, that's a moot point now. Overall, it was fun once it got moving, and I'll still definitely read books 6 and 7, which is more than I could say about the Robert Jordan series after a point. (He's STILL going, too, isn't he? Argh. Stop, dude, stop.)