Another step is that by the defender going for the RB, the QB got away safely. The defender couldn't have made a play either. He would have had to stop and turn around. Had this been NCAA 10, he would have made the wrong read, turned around instantly and tackled the QB in a matter of seconds.
With the new locomotion system, the defender will not be able to turn around and stop you. This is part of the reason the triple option isn't as successful in 10. Even if a defender falls fir the fake, he can still turn and catch you before you get a yard.
Just thinking about it has me worried for when I play GT in my dynasties.