I liked that Dumbledore got another dimension in this book, but at times, I felt a little too much like Rowling kept this information an ace in her sleeve a little too long. I'm not so presumptuous as to suggest how to fix it, but I wish that we had been given even the merest hint that there was another side to Dumbledore. And while some may argue that his off-putting of telling the story of the blackened hand to Harry is an indication that it had a more sinister bent, I think we all assumed that the story had something to do with the horcrux search and it simply hadn't become relevant. Dumbledore's benign wisdom throughout all the books is a bit undermined by the slew of information we get in the seventh installment.
I loved how the revelation of Dumbledore's past subtly showed why he's a stickler for second chances - Hagrid, Snape. And I can see how his early life shaped so many of his words and actions throughout the books, which I think will be a delight when I go back and reread. But I wish we'd had a trace of Dumbledore's other side prior to the hallows. Perhaps that would've made it easier to conclude, like Dumbledore, that Harry had the makings of a better, stronger leader than the only one he ever feared.
Harry does tend to see things a lot more black and white than Dumbledore-- like his steadfast belief, from the very beginning, that Snape (my poor Snape!) was evil-- so maybe Dumbledore thought revealing any of his dark past would have turned Harry off from following his wisdom?
it just seemed so soapopera-ish. i mean it's so easy- him resenting the sister. none of them discussing how effed up to not get her help just bcs they didn't want her to get psychiatric care. and her just losing it in the end- i felt like i'd walked into a biography of tennesse williams! and aberforth just seemed like this one dimensional cantankerous hick. i wanted him to have a backstory, yes, but... also since the wands had memory it wouldve been easy to check to see who had done it right? also i think i wouldve preferred for albus to be more evil than this greater than good thing... we go 6 books with him as this benign powerful character and she sort of cuts him off at the knees. like there is a god, but there is no god. see? he's fallible. and we already have harry for that one. and then he gets to talk to him in the end just so we don't have any confused feelings about him... i was not satisfied with the deathly hollows thread. : D like you left the ring in the dirt? yah. no one knows where it is? no. (yah okay that'll work. what?!)
I was unfazed by how late in the story the information about Dumbledore came, though looking back, I can see how some foreshadowing, particularly in OotP, would have been nice, during the time that everyone was doubting Voldemort's return. Everyone was keen to dismiss Dumbledore then, and some nice juicy dirt would have been just the thing.
I guess we just didn't learn anything that I consider to be too shocking. Who doesn't fall under the spell of acclaim, or sometimes resent the burdens of their families? The friendship with Grindelwald--he was what, 17?
I don't know. I like seeing him as human and flawed--the seeking of the Hallows, I like it, but I'm not freaked out by what we learned.
Yeah, I was a little thrown off by the explosion of Dumbledore backstory as well. You get so much and so little of it fleshed out. But I suppose it is in keeping with JK's attempt to increase the complexity of each book commensurate with the emotional maturity of the children who have been following it since the beginning and are Harry's age. Kids @ 11 want infallible father figures and Kids @ 17 often want redeemable ones.