Unfortunately, the documentary doesn't give a representation of the *attrition* that occurred as the troops engaged. One must rightly presume that Hannibals Heavy Cav suffered losses as it defeated the Roman Cav.
Hannibal only lost 200 cavalry at cannae.

Also CA had written in one of the descriptions (prerelease) that Hannibal still had 2/3 of his original cavalry after campaigning, so I can't guarantee the accuracy of that since it was written for a game description.

I didn't say he wasn't brilliant. I said his center was pushed back and probably routing. There is no way you can use this tactic in RTW.
With a few ironmanrules you may find yourself stuck with a few more losers than you really want. It can be done even with town watch taking the brunt of the load. Hannibal had 4 hours you only get about 1 minute to fully execute this properly.

agree, if scipio didn't had the help of numidian cavalry he probably would have lost, and also if hannibal had better troops he would have won. but that's all after talk. we will never really know
If Scipio's cavalry did'nt return when they did he would have lost. When Hannibals veterans engaged the Roman Princepes and Triarii the Veterans of Hannibal were mutilating them. Unfortanately they were used too late.

As far as the retreating went, theres fallbacks where troops that are tired disengage and retire to the rear. I believe the deep formation of the Roman deployment did not allow for this. This allowed the Gauls to tire the Romans and also lure them forward. While the Gauls got breaks during those 4 hours I'm not sure if the Romans ever did.

So you have tired units in a deep UNMANEUVERABLE formation surrounded on 3 sides and soon to be all 4