If he's on the Sunday then there is a real danger of a very small crowd imo. Also depends on who he's up against of course, but I agree. He is nowhere close to a 'must see' like Elton John or Paul McCartney and has minimal crossover appeal with the youngsters.
Thank God Glasto is huge and there's always something or someone to go see.
Personally I don't want a party, I just want something decent to listen to and watch.....so I'm going to just go with the flow because there are no must sees for me so far and that's ok.