Well, from a personal point of view, I think both teams selected the correct teams to play, at least the combination.
India's batting & SA bowling
I have been saying this for very long and I will at least say it once more that Dhawan is a proper liability. His penchant for 'swag' doesn't go with the test match theme and frankly, after seeing him bat outside the subcontinent for all of last year and before, I don't think he's competent enough to open the batting for India. His technique is clearly flawed and he's not 'Steve Waugh' to fight or guts it out. He's also not your 'Virender Sehwag' category that can't care less whether he's batting on Earth or Mars to simply see ball, hit ball. He's not the mentally most formidable chap and time has come to end this experiment.
As for the other batters? I think Murali Vijay looks more and more classy every time I see him. The one's dismissed by Morkel got proper pearls and would get out again if that was hurled at them. Pujara got out in a disappointing way, but he can't make runs every time. Overall, I thought the SA fast bowlers bowled outstandingly well and credit to them. That Rabada kid is really exciting and if Morkel can keep himself on the park I see he's at the peak of his powers. He will get buckets of wickets in the next 3-4 years.
Now, I don't know the background of Dane Vilas and whether he's having an off series but boy he's poor behind the wickets. I also haven't seen anything in his batting to suggest he's capable of playing ahead of de Kock. I know scores don't come in a series sometimes, but there was nothing substantial in the way he batted to warrant a place ahead of de Kock. Specially, considering his keeping is quite poor.
SA batting & India bowling
Watch out for Jadeja. He will run through the overs and the batting line up if he doesn't have a brain fade on this wicket. As I've said earlier, I dislike Ashwin a lot but for my money he's the best spinner in the world. His control of drift/spin/pace and even the amount of it is mind boggling. To go with it, I think he's settled his mind down with his variations and his accuracy also is reaching relentless levels. Top class. There is lot of talk about SA's batting and rightly so. I don't think half of them have the bottle to sustain relentless pressure from spin. I think Amla and de Villiers stand between India and a handsome lead. Other than that, it's going to be like watching an Indian team in the 90's in SA playing seam and swing.