Harry Potter and the Deathly Hallows – pre-read musings

As many of my readers know, I am a die-hard purist when it comes to modern books originating in the UK. I buy Terry Pratchett and JK Rowling’s books through Amazon.ca so I can get the UK editions.
As a result, I always have to wait for a while before reading the new book. It’s annoying, but worth it.
Especially because I don’t have a big problem with spoilers.
And I especially don’t mind spoilers of HPatDH because I have long expected it to be a fairly crappy book. I’m pleased to note that from the spoilers I’ve read, it seems increasingly to be exactly that.
Obviously, there are spoilers below. Duh.

I can’t really harsh on the book properly until I’ve read it, of course, but here are a few essays I suspect I will agree with: snarky and a bit ranty, well-written in HP-world style.
It sounds to me like Rowling is killing folks off because she can, not because the plot requires it (C’mon, Snape around Voldy and Nagini without an antivenin at hand? Give me a freakin’ break!), and that turns me off (it would enrage me if I had come to expect actual, yanno, plot competence from Rowling). I expect character deaths to be necessary to the plot, dammit, not thrown in as a way of building tension (Joss Whedon, I’m looking at you!). I am very aware that folks can die randomly, thank you, but I don’t read fantasy for its realism. I read it for my enjoyment, and I don’t see how having folks randomly die is supposed to be enjoyable.
All this leads me to wonder what happened to Rowling between the early books, which were so full of whimsy and fun, and the recent books, which involve beloved characters dying for no obvious reason and nary a wisp of whimsy to be found. How did we get from “Nitwit! Blubber! Oddment! Tweak!” to this?
Also, I find it fascinating that so many of us who actively dislike Harry and other characters in the series keep reading them, even though we know Rowling is a second-rate writer at best. I wish I knew what it was about her writing that made it so infectious. Perhaps after I’ve read DH, I’ll reread the series and try to pin it down.