The whole battle could also be framed within the context of Roman class system. Verrus was a commoner and the Roman cavalry at the time had quite the few patricians on it, as they could afford to maintain horses. I think Roman politics might have also played a role in the outcome of Cannae, the rejection of the Fabian strategy and the class divide within the Senate seem to be weak points that Hannibal exploited. Carthaginian intelligence was way ahead of its time.
PS: Movie thread, something something about movies. They all suck anyways.
Cathedral of the Sea, good TV show if you are not averse to graphic depictions of realistic themes (Translation: Its set on the middle ages and doesn't shy away from the dark events of the period, although it is never gratuitous)