Um, have you been hiding under a rock or did you not see the 2014 northern hemisphere tour results - the Wobs were pulverised in all facets of the game and the scrum has always been a constant issue.. Say what you will about provincial rugby between the hemispheres, but international rugby is a different beast and Ma'afu is likely to be as good - although he is playing o/s so spose that counts against him
Your rock is larger than mine I fear. On the EOYT, the Wallabies'scrum was almost always very competitive when the starting players were on. It only became obviously weaker when the reserves and Skelton came into the game. And a large part of that situation was the unwise selection of only one extra prop in the touring side meaning that one of Kepu or Slipper had to play the whole game, each and every test.
Against the Poms, of course, it was the latter's ability to get away with cheating that was decisive at scrum time.
With a full complement of props, now with some half way decent reserves, and Skelton showing all the signs of having put his scrummaging woes behind him, I fully expect the Wallabies will be a whole lot more competitive in the RWC and have no need for the likes of Salesi Maafu or any other Aussie player currntly plying their wares overseas.