The thing that always stuck out to me was the ahem Numbers. If Moses had an army of 603,550 able bodied men of fighting age: Egypt would have been conquered with absurd ease. The Exodus would have been of Conquered Egyptians, not Hebrews. Egypt of the time could have been taken with 60,000 men, never mind 600,000. An army of 600,000 would have scared the piss out of Rome at its height.