You are a golden gawd. That's what I'm talking about. Full Credit.
Nimitz Class History Buff Award.
Although you might have mentioned more about their advisaries. Both Armies were of similar size and training but Caesar raided until the Gallic tribes FINALLY united. Warriors almost alway lose to soldiers despite superior numbers b/c of unit integrity and the inability to change tactis under fire.
Darius's general/cousin(?) was awaiting Alexander at Granicus where ATG bull rushed them at dusk, crossed the river and up hill under massive fire and proceeded to skull **** the Persian forces (and almost died if not for Phillip's man Black Cleitus).
He then killed 10,000 Greek mercenaries that night to make his point about Hellenistic unity.
Of course, the Battle of Gaugamela was pure genius and had Parminian held the left flank allowing Alexander to capture Darius history would have been VERY interesting.
Alexander fought trained soldiers HOWEVER the Gauls were fighting for their homes and for their way of life. Darius's army was pooled from conquered regions with no love for Darius or Asia Minor.
In the end I go with Alexander. Just because of his ability to mix passion with adaptation. I would have been loyal even into India and beyond.
Here's the real question. Could Alexander have defeated The Chin? No way.
Racing is life. Anything before or after is just waiting.
Steve McQueen