Listen, Washington was just a highly replaceable commander of some creole rebels. If Washington's mother had died in childhood, everything would have been more or less the same. The rebels would have rebelled, they would have appointed an experienced commander as chief, they would have won, and the ideology common to Englishmen in America and Britain would have been used to "form" the "new nation". That's boring, I know, but it's the way of it. Fact is, neither Washington's America nor even Lincoln's mattered to the world. FDR's America and Eisenhower's did.
If you're gonna go down the chaos theory route, you might as well make Columbus' great-grandfather leader!
What's the difference? If you're the head of a nation 16 years after a baby-boom, should you get the credit for the increased power of your nation?