I can't see Barnes coming back into the starting XV. I think that the backs have been really starting to get some combination going, especially the midfield of Foley, Horne & AAC (Adam Ashley-Cooper). The wingers, I'd have 2 of Mitchell, Crawford & Kingston as Betham makes too many mistakes. Folau is killing it at 15 (the Sth Africans and Kiwis can see it, but many Aussies still seem to have doubts - not sure why) - why would you want him to watch Barnes in action. Barnes is a completely different type of player - a smart foootballer, but the kick is his default option and he rarely looks to counter. I spent weeks asking for Lucas to be given the opportunity and although I don't think McKibben is the answer long term, Cheika as persevered with him for 11 weeks so I can't see that change happening.
Before concluding, I'd like to address the issue of Folau making elementary mistakes. From time to time, yes he does something which points to lack of rugby experience, but there are players in that team who have been playing rugby since they were 6 making exactly the same type of basic error. At least Folau seems to learn from his mistakes and rarely repeats them, some of these guys do the same dumb things every week.