When I read the afterward, I found that he contemplated that the true energy drove Japan to the World War 2 was not the elite military but middle class soldiers who could not admit the shame. Card thought that if any power pursued middle class soldiers to think to stop and keep independence of Japan is not a shame, then, the history might be changed.
Though I didn't liked him written that he is not sure to avoid the World War 2 is good or not, because nuclear bombs dropped on Japan read Japan to open to democrat country and stimulate the economic growth, I think there lies some truth in it.
As reading this afterward, I came to think that Little Doctor, the final weapon, represents the nuclear bomb, and Ender and other characters try hard to stop it destroy the planet.
The ending of this book is worth to be the last of this great saga. But one day, I would like to read what was "descoradores". If you have not read the Ender's Saga yet, why not try from the first book, "Ender's game".