That would still mean Jesus had to choose one person that would have betrayed him. That means he chose a man who had a weakness or bad tendency just to play on or use that weakness to fulfill prophecy. That "other man" would be just as doomed as Judas without ever know he was chosen to fulfill an evil role. Instead of trying to cure that persons bad tendencies you promote it. What's worse is that you know the person will fail before the person with the weakness ever does. It's like being a heroine addict and someone using that addicted to their advantage or for a purpose.
The predestination either started when those words were prophesied or when Jesus chose someone knowing they would fulfill that role.