Nothing JKR can do about it at this stage, you mutter? There is! I came across this idea of genius on Kboards from Landon Porter, an open letter to JKR:
"I am about to offer you two words that will transform that mountain of money into a money continent. I understand completely how you might have overlooked it, but as a fan of comic books, it was thankfully not lost on me.
Ready for the two words:
Alternate. Timeline.
Seriously, you've already introduced time travel into your universe with the time turner. It's time to stop worrying and love the paradox.
Imagine if you will, the loved ones of one of the victims of the final battle deciding to stop it before it even starts by using the time turner to go back to the first rumbles of trouble: the Chamber of Secrets scare. There (er... then) they set in motion events that end with Dumbledore explaining exactly what the book was then and setting up the quest to destroy the other clearly-no-a-lich's-phylacterys then and there.
Of course, this will involve sending his crack team of The Chosen One and plucky sidekicks and will put into play a whole new sequence of plots for a whole other series of books where you can rearrange your pairings however you want (and also let Sirius live).
As a bonus, killing Voldy early will allow the next set of movies to have a Big Bad who doesn't look like The Master from Buffy got it on with a seal."
I see no flaw in this plan.