I'll say Alexander was far above the average general. Yes he was one of greatest but in my opinion he is not greater than Hannibal. He was undefeated (though he lived a very short life) and that means something, but was the persian empire really that strong? Alexander's phalanx and cavalry were both superior to the persian counterparts. He was outnumbered but his troop quality was waaay better. I think Hannibal and possibly even Pyrrhus with Alexander's forces could have accomplished taking Persia.
Split off from the Alexander thread.