The current rule makes the most sense. If one remembers who has possession the ball before it went into the end zone, then the rule is consistant. If you are the last person to have possession of the ball when goes into the end zone before going out of bounds, either on the side line or the back end of the end zone, it is a touchback and the ball goes to the defense at the 20 yard line. If it recovered within the end zone by the offense it is a touchdown. If it is recovered in the end zone by the defense, it is a touchback. When Foreman knocked the ball out of the runner's hand, he was the last to have possession of the ball in bounds. If the ball had stayed in the end zone and the ball carrier recovered it, it would have been a touchdown. If a Tennessee had recovered the ball in the end zone, it would have been a touchback.
I think/hope it got all of this correct.