You guys both wrote what i wanted but i am on phone at work. Couldnt agree more.
The problem i see is also that if there is not enough non-electronic names on the lineup, festival will lose a big portion of the audience and limit itself to a smaller group of the audience they can appeal to.
Absolutely cannot do arenas in the UK. Biggest venue in the last decade has been the Eventim Apollo although he did play three dates in the end. Usually does academy tours.