There are quite a few acts touring around Glastonbury who'd be a lot "fresher" and make the headline look more diverse. For example: Beyoncé, Pink, Florence, The 1975, Harry Styles, The Weeknd.
Most probably the festival tried to book some of these acts and wasn't successful in the end, fair enough. And we all know that there'll be so much going on and great alternatives to choose from when we arrive at the farm. But still, right now, discussing what looks like to be the biggest 3-4 acts on the poster, it doesn't look "Glastonbury-like". And it's ok to state that, even though each booking individually is a reasonable one.