Hey...U'd probably get more hits in the history forum so you should PM a mod or sum1 to move it.
Anyway, collect a series of opinions on him. If I remember correctly it was Plutarch that attributed a lot of his actions to fortune. And many medieval theologists similarly attributed it to God's provinence so in essence it wasn't his own actions but a form of luck that helped.
Ian Worthington is one of the historians who evaluates his greatness in his essay "how 'great' was alexander' and can be found online.