Another thing I'm wondering.
Remember how she's spent 6 books telling us in almost every one how wizards can get hurt like Mugglesx1000 and not die--like falling out windows and bouncing, or falling from a broom umpteen feet off the ground, or regrowing all their bones or whatever? Or all those crazy freaks in the waiting room at St Mungo's and stuff?
How did Fred get killed by a wall? Does that even make sense?