Well it would have been great to have The Beatles, Stones, The Kinks, T-Rex, Bowie, Bee Gees etc there. Of course for various reasons many of those sadly couldn't be there. I presume The Stones and Bowie turned it down. Other acts like The Who, The Smiths, Oasis, Coldplay just wouldn't have been suitable. In the end rock and roll is anti-establishment.
Would love to have seen Jarvis Cocker sing Common People though.