Not only is this book NEEDLESSLY overly violent, but it is very poorly written structurally, and has many negative aspects to what it presents to readers of any age. It's educational value is more along the lines of what NOT to do, rather than to do.
The first part of the book seems mostly dedicated to Rowling going on a Jason Voorhees-esque rampage against the supporting cast, killing off secondary characters right and left, beginning with the pointless death of Harry's beloved owl Hedwig. This is supposed to show that Voldemort Is Now A Serious Threat. This is a theme that continues throughout the novel as various names we've heard before are trotted out and shown to either be dead, imprisoned and/or tortured, fled, or otherwise come to a bad place.
There is a sense of desperation about the book, ostensibly that of the Trio's quest to find the Horcruxes, but really it's the desperation of the reader wanting the author to FINALLY allow them to make some sort of progress. They wander here and there all over the countryside with no apparent plan, and some enigmatic clues that will only slowly over the course of the book one by one become mysteriously understandable when the author ALLOWS them to be.
Harry in particular comes off looking hapless and helpless with no idea what the heck he is supposed to be doing. Well, I suppose that's fitting, since Rowling has spent 6 books prior treating him like a mushroom (keeping him in the dark and feeding him manure). Over the course of the book, Rowling spoon feeds the character successes, and the readers information, and always through an outside agency. Harry is only allowed to accomplish a victory when Rowling wants him to do so, and through no effort of his own. Indeed, the harder he tries, the worse things get.
More pointless deaths follow as the Trio gets pushed too and fro some more, again for no apparent reason than to build desperation on the part of the reader for SOME story progress to be made.
During the course of events, we learn (what many of us suspected) that Dumbledore did indeed know what would happen to Harry at his Aunt's home, but chose to put him there anyways for the cause of the Greater Good. Dumbledore thus stands guilty of at the very least criminal neglect of a child, if not actively aiding and abetting child abuse by sending him back to the Dursley Prison every summer. We also learn that DD is something of a fascist in his youth, having been a close associate of Grindlewald, the wizarding version of Hitler in WW II.
Rowling also tries to "redeem" Snape by showing us how much he loved Lily Potter, and how much he strove to make amends after HIS betrayal of the prophecy to Voldemort set the stage for their deaths.
As if that were enough to make up for his horrid treatment of Harry for 6 years, or his professional misconduct against virtually every non-Slytherin student he comes across. Sorry Jo, not buying it, let alone that Harry would EVER give a child of his the name Severus in any way shape or form (or Albus for that matter...see the execrable Epilogue).
The ultimate confrontation between Light (Harry) and Dark (Voldemort) is both anti-climactic and a bit disturbing. The "brawl for it all" at Hogwarts is told mostly in the form of brief glimpses of various characters as they pass briefly by with little fanfare or comment.
THIS is the payoff of 6 books worth of making us care about the school and these characters? Sad...so very sad...
And the ultimate stupidity is finally upon the reader...the power Harry has that Voldemort knows not is to die. Yes, Harry beats Voldemort NOT by dint of anything he really does, or learns or becomes, but by letting Voldemort hit him with another AK. Thus Harry is marked forever NOT as a hero, but as a pawn of fate who wins not because of any heroic deed or trait, but because Prophecy (aka the author, Rowling) says he will.
Again, is that the sort of lesson you want people to learn? We're all helpless before Fate. Nothing we do can change our lot in life. We just have to accept it and let it happen...
And the less said about the horrific Epilogue, the better, with particular dishonors to the aforementioned Albus Severus, for one. and Harry marrying Ginny the Potions Princess for another (remember that little scene with her and her Mum in Book 5, then go back and reread book 6 with new eyes)...
A poorly written book with extremely BAD messages that I think many people gloss over on the strength of Rowling's one true artistic trait: her generally engaging style and that up till this point covered up just how truly wretched a writer she really is.