I'm kind of in two minds about Australia. Part of me thinks they could slip under the radar and get into the final (a lot of challenges along the way of course). But to do this they'll have to be consistently good, not get too sloppy, and try their best to remain injury free (beyond their control really). The last one is important because as was pointed out, Pocock is mammoth for them in so many ways. Regardless of whether his technique was always legal, he and Hooper in tandem were a major part in making our forward's job difficult in Sydney.
I would also suggest the Wallabies will want to avoid a situation whereby Quade Cooper has to come into play 10. That should be fine against Uruguay. But a nightmare against England, and very risky against Wales. The guy has an eye for holes in the defense and can put the foot down to create all sorts of havoc. But he can also botcher restarts when under pressure, throw crazy passes that don't work out, and be totally off with the placement kicks.
On paper the Wallabies have a fantastic squad though. Just amazing. But there are a lot of variables for them. I would also like to give Stephen Moore a mention. I think he's vitally important for them. When they come up against physical packs like England, Springboks, and the All Blacks then he's the type of guy they need. I'm also going to quietly observe how they perform when the pressure truly comes on. They won the Rugby Championship, but they had a very favorable draw where they played the Boks and ABs at home in a shortened competition. There's little doubt in my mind they go up a couple of notches at home. But now they don't have those comforts, so we'll see.