@Flem
Key word, "Last Time" - The last couple of seasons, the amazing run of form he had has been dropping away, which coincided with what two events? 1. His back issues starting to flare up massively and 2. No longer having Ponting or Hussey in the side to soak up some of the pressure he now faces as being the best batsman in the squad. He's generally walking out there now thinking "Well, I can trust Haddin to do a job for me... but Steve Smith? George Bailey?" and in this series, he's generally done it when Australia are two down for not many.
His achievements against South Africa are great, he averages something like 70 against them from memory? But how many of those runs came at #4 without a consistent pair of opening batsmen, a world class #3, #4 and #6 being in the team beside him?
@Hendrix
Look at this series, how many did Warner score when the game was live? He made hardly any first innings runs and had the benefit of coming in to a second innings almost always with England completely out of the match. He's a great talent for see ball, hit ball but he doesn't have a Hayden like ability to do it consistently under pressure in all conditions.
Harris is the best bowler Australia have produced since Glen McGrath and possibly even as good if not better than McGrath, problem is he's amazingly injury prone and has been helped through this series by the fact that he's not been asked to find 25-30 overs across 2 days very often. Reports indicate that he has knee fluid leaking into his calf muscle causing major problems, that his hip on the opposing leg is starting to buckle and that he was touch and go for pretty much every match, assisted by the fact that Australia batted first in all three starting matches. I'm not questioning his talent, I'm questioning his ability to stay on the park if South Africa bat 140-160 overs in their first innings.
Lyon benefits when his team are steam rolling, he doesn't take too many when they're not. If Johnson does a Patrick Cummins over there and rips apart the South Africans, Lyon will be a good chance at taking wickets. If Lyon finds himself bowling against a settled De Villers, Amla or Du Plessis, good luck. I don't see him being at all effective against them.