I think Harry Potter is on a level above Ender's Game in terms of ambition. Rowling does some pretty impressive things in her novels.
But in both cases, it helps to look at why the authors make their heroes despised. Card does it to isolate Ender, to force him into being brilliant when he really doesn't want to be a hero. That's the theme that underscores the original four books.
In Harry Potter, it's done because Rowling marks Harry as this object of perfect good. Not as a perfect character, mind you, but a character that serves as a metric against which the other characters are judged. And so Harry finds himself disliked by certain other groups throughout the series, and it's almost always used to illustrate a certain vicious aspect of personality (be it class/race warfare, or glory-seeking, or bureaucracy).
But in both cases, it helps to look at why the authors make their heroes despised. Card does it to isolate Ender, to force him into being brilliant when he really doesn't want to be a hero. That's the theme that underscores the original four books.
In Harry Potter, it's done because Rowling marks Harry as this object of perfect good. Not as a perfect character, mind you, but a character that serves as a metric against which the other characters are judged. And so Harry finds himself disliked by certain other groups throughout the series, and it's almost always used to illustrate a certain vicious aspect of personality (be it class/race warfare, or glory-seeking, or bureaucracy).