If they bring this rule in then your just going to end up with teams camped in there box, would make playing a high line absolutely pointless since an attacker can gain a yard advantage on the defender before the ball is near them.
As much as I dislike him the fat man at spurs got it spot on when asked about the blue card rule, basically every other sport is trying to streamline there product to make it quicker, we are going the opposite way and trying to bastardise the sport.