OK, I was actually at the Soundwave festival last night and saw Slayer so let me clear up some issues/errors.
Firstly, yes it is a short set, but they only had an hour to play. That being said, they could have probably squeezed in another tune - there was too much 'dead air' between songs.
Secondly, Gary Holt was PERFECT. Seriously, he nailed everything, and he kept the solos fairly close to the originals. Also, his stage presence is better than Hanneman,
Finally the set is slightly out of wack. They most certainly DID play 'Angel of Death', it was their final song. 'Black Magic' was actually played at the end of 'Raining Blood'. Basically they played 'Raining' all the way through, until just before the final insane thrash/guitar solo section. At that point they let the feedback hang, and threw in an interlude of 'Chemical Warfare', then moved onto 'Black Magic'.