Well it was an amazing festival, and although Linkin Park were one of the stronger bands on Saturday, that is hands down the worst I've seen them. Really didn't seem like they were all that interested, and they had one of the worst stage set ups I've seen for a festival headliner.
Musically there were few faults, but there was a real lack of the crowd interaction I've come to expect from LP. The crowd didn't respond too well either, hardly any movement or singing as far as I could see (and I was about 4 rows from the front). Didn't help that they finished around 15 minutes ahead of scheduled, too.
Also the DBS set within the encore was a complete atmosphere killer. The crowd weren't into it at all, and it just didn't seem right for a side-project to get a main stage headline crowd. If they were to play at any point in the weekend, it should've been an early afternoon slot in the tent.
I recall an interview a month or two ago, where the band were speaking about wanting to become considered as the best live band around; based on their Knebworth performance, they're far from it.