Jonathan Agnew alluded to a perceived lack of leadership from Hashim Amla. I don't know how true that is, and he would know more than me, but I suspect not too much unless someone has been blabbing to him. In theory that should be a very strong batting lineup, with someone like Duminy coming in at 7 when he ought to be at 5. Amla and ABdV are genuine greats IMO.
They do appear to be trying to cover up batting weaknesses by playing just 4 frontline bowlers. For years I felt England got it wrong by doing the same, and I'm really happy with the England bowling balance now. They're not all world class, but they all seem to play their part. The batting if anything is just a little too deep, which means Bairstow at 7 and Moeen at 8, when both really ought to be a position higher.
Pleased for Compton. I supported leaving him out originally, as I felt he was so uptight it would only go downhill, and at the time there were plenty of other options in the batting. As the rest of the contenders have dropped away, he looks very much right for the current side, as does Taylor (who should have been a fixture in the team well before now). Hales seems caught between trying to prove he can adapt to test match cricket, and playing his natural game. I think success lies in working on a little more caution outside off stump, but apart from that trying not to tinker too much. It is never going to turn out well if a player has to learn a new style whilst playing their 1st few tests.
regards
Ian
p.s. whilst not a huge fan of Kallis, he is exactly what this current team really need now - a quality batsman and capable 5th bowler.