Time will tell if standing the mark still has the benefits you suggest given they now have to stand still until the umpire says they can move.... and the kicker has already made his escape or got his kick awa..
It won't be as good as before, but if your opponent marks the ball and you're close to him it's still way better to man the mark and stop him instantly running forward and playing on than running backwards and seeing the ball fly over your head...





