And the rider's fit to the bike has a big impact on handling as well. If you take pair of bikes with the same geometry but slightly different frame sizes, and set them up to fit the same rider, the rider will find that they handle differently.
Well, it may satisfy you to know then that the 73/73 frame is a 25" and the 72/71 is a 23". Stem is slammed on the 25 and raised on the 23, bar heights are within 1/8".
It would take some convincing, though, for me to be sold on frame size being a bigger factor than geometry in this case.