I believe the new rules makes it compulsory for both teams to hook for the ball, which now counters the above.
There's been a few amendments relevant to this issue.
-First one is that a player in the front row from the team feeding the ball must strike for the ball, otherwise its a penalty.
-The second amendment designed to offset the loss of advantage of the first amendment ,is that the scrumhalf aligns their shoulder with the centre of the scrum allowing them to stand closer to their own props rather then down the middle, which means the team feeding the ball is still offered an advantage as the ball is now fed at the feet of the front row, rather then half a meter in front. The ball must still be fed straight.
-Finally the number 8 is not allowed to reach in further to retrieve the ball, he can now grab it from the feet of the locks where previously he had to wait until it was at his feet.
All in all its designed to speed up the scrums, and now rather then trying to drive over the ball, hookers and front rowers are again been encouraged to hook for the ball. Whilst the defending team may have the advantage of an 8 man shove, the attacking team has the benefit of a faster scrum if they feed and hook accurately.
So if we throw our mind back to the 2015 RWC in the match against Fiji, the Wallabies would have been penalised because no one in the front row hooked for the ball, instead they were trying to drive over the ball.