I do agree that you want your headliner to put on a party. So much as I love Neil Young, and he'll surely be the greatest artist playing the festival next year, if he's headlining and he's up against, say, Ezra Collective, he might lose. It's also why I think Beth Gibbons or Laura Marling would be wasted at the top of the bill, on any stage, though they're both absolutely great.
I'm still hoping Pulp or Massive Attack might turn up, though there seems no sign of it.