On a side note - something related to having "repeated headliners" vs "new-blood headliners" discussion:
Here in India, I visit pubs/bars that play rock music. There is a particular place that we, as a group of friends, visit thrice a week. We know the DJ. We know the usual playlist that is up for a given night. We constitute, probably, 5% of the customer base. We want the DJ to play new songs that we have discovered. But the rest of the customers demand for the usual ones - Zombie, Killing in the name of, In the End, Boulevard of broken dreams, Its my life, Summer of 69, Bohemian Rhapsody, and such. Now, all these are great songs. But we just have had so much of them that we want something new. But the place needs to sell. It needs customers other than us.
On similar lines, I understand and appreciate that festivals like GMM need to repeat because they need to sell and disappoint a few regulars. Ahem, GnR is OK is all I am saying