To be honest, the defensive coverage AI improvements in man and zone coverage aren't very evident to me so far; I assume that's due to a low difficulty setting to accommodate new players (E3 is focused towards members of the general press, not necessarily from the football gaming media).
Demonstration of those improvements likely is going to have to come in an extended blog post from Tiburon detailing exactly how that AI has changed, and/or extended hands-on time with the game from a respected member of the sports gaming community. For now we just kinda have to take Tiburon's word for it. Still plenty of time for either to happen.