How does the ending of The Kite Runner create a lasting effect on the reader?

While some readers reported being disappointed with
The Kite Runner's ending because of its lack of complete
resolution, many critics have interpreted Hosseini's ending to be a portrait of
Afghanistan's future--tentatively optimistic.  Sohrab does not speak to Amir and Soraya
at the book's end, but he does show a faint smile, a sign of future healing.  Similarly,
the country of Afghanistan (when the book was first published) was showing signs of
finally being able to choose its own leaders and establishing the type of nation that it
wanted to be, not what others tried to impose upon
it.

This concept of hope leaves a lasting impression with
readers as does the tidiness of Amir's redemption.  At last, he has sacrificed for
Hassan instead of sacrificing someone for his own sake, and he takes on the role of kite
runner for Hassan's son Sohrab.