OK then;
Dumbledore is dead. Dead is dead according to JKR in several interviews after she killed off Sirus. If and when our beloved headmaster reappears it will be in a maddening non-answer/conversation with his picture somewhere.
The reoccuring theme of socks is puzzling. Either a funny ha ha goof inside joke (hi Opal like thing) on her part or a minor plot point that will have some bearing.
Why does everybody say Harry has Lily’s eyes?
Will a beloved character live or die? Anything is possible, but I can’t see any of the big three crumping in a kid’s book.
Aunt Petunia and the communication with her and Dumbledore has to be explained. She knows a lot more about the wizard world than Vernon knows. She knew about Azkaban and the howler hinted at something. We know she is not a squib. (JKR said so)
Ollivander is missing. Was he comissioned to make a new wand for Voldy to avoid a repeat of what happened in the graveyard?
Will the first chapter fast forward over a chunk of the summer with Harry and the gang already figured out the locket was found by Sirus’s brother and they already dealt with it? It will save time and pages.
I like the idea that I read somewhere on Mugglenet or the Leaky Cauldron editorials that Snape while interviewing at Hogwarts 17 (or so years ago) at the same time as Trelawney heard the entire prophecy and only told Voldy half of it. That’s why Dumbledore trusts him. Also it allows for the Snape looking out for Snaple angle.
Voldy doesn’t know love. Some how and some way, Harry will demonstrate that to him in the final showdown at Hogwarts. (I like the idea of the final battle being there because it’s a central place for all the stories.) Lily’s love for him, Harry for his friends and the Weasley family and who the hell knows Aunt Petunia, Uncle Vernon and the pig tailed brat all might come into play.
An elegant solution would be him being stripped of all magic in the fight and fitting into what she said that the last word of the last book is scar.
“Harry awoke from his dream and not needing glasses with his perfect eyesight looked into the mirror and saw his short neat hair and no sign on his forehead of a lightningbolt shaped scar.”

Ok that last made up quote is a goof on my part. A dream would cause rioting, but it wouls be OK to me if he became a squib to save the world.
A nice ending to a kids book that the hero gave up everything he held near and dear to his heart as a sacrifice to the greater good of the world. The last chapter as a coda would have him riding off into the sunset. Not happy or sad but knowing he did the right thing and living as a muggle.